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Reading Description:

Wahlqvist, M. L. (2002). Introduction to human nutrition. In M. L. Wahlqvist (Ed.), Food and

nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 3-10). Crows Nest, NSW : Allen & Unwin.

Read, R., & Jones, G. P. (2002). The food supply : the Australian food system. In M. L.

Wahlqvist (Ed.), Food and nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 39-47). Crows Nest, NSW : Allen & Unwin.

Briggs, D. R., & Lennard, L. B. (2002). New and emerging developments in food production.

In M. L. Wahlqvist (Ed.), Food and nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 115-134). Crows Nest, NSW : Allen & Unwin.

Rutishauser, I. H. E. (2002). Contemporary food use : food supply and food intake. In M. L.

Wahlqvist (Ed.), Food and nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 152-165). Crows Nest, NSW : Allen & Unwin.

Rutishauser, I. H. E. (2002). Nutrition assessment and monitoring. In M. L. Wahlqvist (Ed.),

Food and nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 499-507). Crows Nest, NSW : Allen & Unwin.

Wahlqvist, M. L. (2002). Food, individuals, environment and policy : the history of food and

nutrition policy. In M. L. Wahlqvist (Ed.), Food and nutrition : Australasia, Asia and the Pacific (2nd ed.) (pp. 582-584). Crows Nest, NSW : Allen & Unwin.

Reading Description Disclaimer: (This reference information is provided as a guide only, and may not conform to the required referencing standards for your subject)

Introduction to human nutrition Mark L. Wahlqvist

OBJECTIVES

• To provide an understanding of the dimensions of human nutrition.

• To explore the origins of human food culture.

• To provide an historical basis for deductions about preferred ways of eating in the contemporary world.

• To consider the long~term and unintended consequences of changes in the human diet.

THE DIMENSIONS OF HUMAN NUTRITION

The study of human nutrition encompasses a remarkable breadth of topics. These include the genetic inheritance which determines each individual's susceptibility to disease, and the influence of the physical and social environment which determines whether disease occurs. New knowledge of the human genome is going to revolutionise our understanding of disease, and the interplay of nutrition and disease. It may be that in the future a 'reading' of a child's genome will provide the basis for dietary requirements necessary to prevent the occurrence of particular diseases. Chapter 25 provides a discussion of the genetic basis of disease and how the genome interacts with nutrition.

Whereas the genotype is the underlying gene-plan of the body, the phenotype is the actual body as constructed, allowing for the dominance of certain genes and environmental influences on development. The influence of environment needs to be considered in two ways; first in terms of the environment in which each individual was conceived and developed in utero, followed by early nurturing and breastfeeding as an infant. New information suggests that the health and

3

4 • Part I Human nutrition: The concept and context

nutrition of the mother can influence the health of the child n~any years later as an older adult, particularly with regard to diseases such as heart disease and diabetes (see Chapters 27 and 28). The second consideration concerns the many aspects of the environment as they currently act on the individual. These include the physical environment which encompasses climate, shelter, water, food supply, conditions of hygiene, and the social environment which includes t1mily influence, social supports and obligations, work, money, and government regulations.

Food is part of the human environment and, in an ideal world, just the right amount of safe and nutritious food would be consumed so that each person would have the best chance of achieving optimum health and long life. But, of course, it is not as simple as that. Not all available foods are equally nutritious. The quality of the foods consumed is the result of several factors: (i) government regulations regarding a safe food supply (see Chapter 9); (ii) what foods are supplied by farmers, food manufacturers and supermarkets (see Chapter 4); and (iii) what foods we choose to buy and eat (Chapter 10).

One of our authors, Pat Crotty, likes to divide nutrition into 'pre-swallowing' and 'post-swallowing' aspects. The 'pre-swallowing' considerations can be divided into those that deal with the food supply and those relating to our human individuality and the anthropological and sociological influences that determine what we choose to eat (see Chapter 3). The 'post-swallowing' aspects concern the physiology of nutrition including nutritional requirements for energy, protein, vitamins, and the consequences of too little or too much of these nutrients. Knowing just what nutrients are required and how much of each is complicated. It is not possible to do experiments on humans as might be done with laboratory rats. Certainly, the nutritional requirements of rats-which are, like us, mammals-are similar to human requirements but not exactly the same. Information on nutrition is drawn from two major sources; one is laboratory science, where experimental animals are used, and to a lesser extent, human subjects are used as well. The other main source of information is epidemiology-the study of nutrition and disease in populations. Epidemiology shows up relationships such as an association of heart disease with high intakes of saturated fats, or a higher incidence of the congenital disease spina bifida with low intakes of the B-vitamin folacin. Where such associations are found, laboratory

science takes over to determine the nature of cause and effect.

Very often information is not clear-cut. Statistical analysis must be used to determine whether a certain finding might have arisen by chance or not. Even so, knowledge which seemed firmly established may change as continuing research uncovers new information. Assessing the significance of new information can be complicated. Scientists do not necessarily agree and arguments may go on for years before finally being settled one way or another. Some people in the nutrition field may be selective about what they believe. Sometimes their reasons are religious or they may have a financial interest in proclaiming certain 'facts'. With the introduction of computers and the internet, information is no longer hard to find-the more difficult problem is sorting out factual information from that which is biased (see Chapter 2).

EVOLUTION AND THE HUMAN DIET

It might reasonably be assumed that human beings evolved in association with particular diets and that the physiology of the human body is adapted to maintain health on those diets. Thus, the more we understand about what early humans ate, and their state of health, the more we are likely to be able to optimise present food consumption for physical and mental well-being and longevity. Research into the lives and nutrition of early humans is continuing in many parts of the world, particularly in Africa and the Middle East. There are three main ways through which we rediscover these early patterns:

anthropological study of early human ancestors (Eaton and Konner 1985; Bryant 1994);

2 the study of contemporary communities that have retained earlier dietary patterns, notably huntergatherer societies such as Aboriginal Australians or Malaysians (Orang Asali) (Chong 1975) or Kung Bushmen in Southern Africa (Truswell and Hansen 1968; Truswell 1977);

3 the study of the human genome and how genetic expression may be affected by food intake. Studies of Aboriginal Australians have shown, for example, that Aboriginal physiology is adapted to maintain better health on bush diets than on 'Western' diets rich in saturated fats and sugar. The studies ofKerin

O'Dea on the metabolism and health of Aboriginal Australians typifies this approach (Temple and Burkitt 1994).

ANTHROPOLOGICAL STUDY OF THE HUMAN DIET

Anthropologists reconstruct earlier ways of eating by various methods including:

the examination of middens (cooking mounds) and burial sites for evidence of the types of food eaten (Meehan 1982);

2 the study of coprolites (fossilised or hardened preserved faecal specinLens) for indicators of foods eaten, such as fish scales or grains (Eaton and Konner 1985);

3 deductions about the ecosystems of the period and their potential for producing various kinds of foods (Hetzel and Firth 1978; Woodward et al. 1987);

4 detailed examination of teeth and jaw development as indicative of types of foods eaten (Katzenberg et al. 1993).

Evidence of the health of early humans comes principally from human remains, which are usually skeletal, but there have also been a few spectacular finds of mummified and frozen corpses for examination (Polosmak 1994; Spindler 1994). These remains have indicated that:

1 Hunter-gatherers were able to live apparently healthy lives at least into their seventh decade.

2 They were sometimes taller than subsequent generations, suggesting that the overall food supply was better and susceptibility to recurrent disease less. Recent increases in human height which have been documented in Scandinavia, through studies at the Stockholm Museum, followed a low-point in height after an earlier taller hunter-gatherer population.

CONTEMPORARY AND ANCESTRAL HUNTER-GATHERERS

From the work of Eaton and Konner (1985) it is

possible to make the following deductions about the paleolithic (Pleistocene, 400 000-45 000 BC) diet:

Chapter 1 Introduction to human nutrition • 5

There were appreciable quantltles of low fat animal-derived foods (see Table 1.1).

2 Plant-derived foods were unrefined.

With regard to nutrient intakes (Table 1.2):

1 For macronutrients, protein was a relatively high, and fat a relatively low, contributor to energy intake.

Table 1.1 Proposed average daily macronutrient intake for late paleolithic human beings consuming a 3000kcal (12 500 kjoule) diet containing 35% meat and 65% vegetable foods

Macronutrient Intake (g)

Protein 251.1

animal 190.7

vegetable 60.4

Fat 71.3

animal 29.7

vegetable 41.6

Carbohydrate 333.6

Fibre 45.7

Source: Eaton and Konner 1985

Table 1.2 Comparison of the late paleolithic diet,* the current American diet, and US dietary recommendations

Total dietary energy (%)

Protein

Carbohydrate

Fat

P:S ratiot

Cholesterol (mg)

Fibre (g)

Sodium (mg)

Calcium (mg)

Ascorbic acid (mg)

US Senate Select

Late Current Committee paleolithic American recommen·

diet diet dations

34 12 12

45 46 58

21 42 30

1.41 0.44 1.00

591 600 300

45.7 19.7t 30-60

690 2300-6900 1100-3300

1580 740§ 800-1200~

392.3 87.7§ 45~

* Assuming the diet contained 35% meat and 65% vegetables

t P:S denotes polyunsaturated: saturated fats

t British National Food Survey, 1976

§ U.S. Department of Agriculture Food Consumption Survey,

1977-1978

1f Recommended Daily Dietary Allowance, Food and Nutrition Board,

National Academy of Sciences-National Research Council

Source: Eaton and Konner 1985


2 Relatively high cholesterol intakes were tolerated, but against a dietary background high in fibre and low in fat (with a high P:S ratio).

3 Salt (or sodium) intake was relatively low and the potassium: sodium ratio high.

4 Calcium intakes exceeded those in industrialised societies today.

5 The diet achieved upwards of 400 mg vitamin C (ascorbic acid).

These deductions depend on ancestral and contemporary anthropological studies of hunter-gatherers. There are some important conclusions to be drawn about this work, along with related studies:

Foods derived from the sea, rivers, lakes, or streams consistently played a role in human nutrition.

2 The intake of animal-derived fat was low because the creatures caught were undomesticated-the fatty part of a hunted animal, like that in the breast of a gazelle, was highly prized. The fats from wild animals are much less saturated than from current domestic herbivores. Plant-derived fat was relatively unrefined, mainly from seeds or nuts.

3 Cholesterol intake could be relatively high (500-600 mg/day), from land and sea creatures combined, but was not accompanied by significant amounts of animal-derived fat.

THE HUMAN GENOME AND ITS EXPRESSION

The first 'humans' appeared about 4 million years ago and the earlier forn1 of Homo sapiens about 400 000 years ago. The human species, as we know it, has existed for about 200 000 years, or some 6000 generations, as judged by studies of genes in mitochondria, which are independent of genes in cell nuclei and derived unchanged from the mother rather than from fusion of sperm and egg. The mutation rate of mitochondrial DNA is well characterised and allows an estimate of the age of the species. Anatomically modern humans (Homo sapiens sapiens) appeared about 45 000 years ago. It is likely that, in the 300 or so generations since the emergence of subsistence agriculture, most of the genetic attributes of the hunter-gatherers have been retained, whether or not these are now advantageous. Among the genes concerned are those which

apparently increase the efficiency of energy expenditure (reduced metabolic rate) when food supply is limited, (the so-called 'thrifty gene' or genes expressed as a 'thrifty phenotype') (Zimmet 1993). Now, of course, with an abundant food supply and less physical activity a 'thrifty gene' or 'thrifty phenotype' which conserves energy may predispose to obesity and its complications, and therefore becomes a risk factor for a range of diseases.

FOOD BELIEFS AND CULTURE

It is difficult to retrieve information about the entire food culture of our ancestors, especially the belief system which would have developed out of observations about food and health, and social and personal experiences of food. Efforts have been made to deduce the origins of food beliefs now bound up with religious or other cultural terms (Farb and Armelagos 1983). For example, what are the origins of beliefs about the undesirability of pork in the human diet in religious systems whose origin is in the Middle East, namely Judaism and Islam, but not in major food cultures like that of the Chinese where pork is prized? Is it that infestation with the pork tapeworm (cysticercosis) could only be dealt with by food exclusion and religious law, while in the Chinese culture the problem was overcome in other ways? Or is it simply that the habits of pigs were regarded as filthy and risky by some cultures, but not others?

Fasting, which is often partial or periodic, is part of many religious traditions, such as Christian orthodoxy, but may have been a societal way of achieving equity in food distribution or eking out lin1ited supplies of certain commodities, for example meat. Such intentions, overt or covert, may have had biological justification in terms of preferred meal patterns, or avoidance of over-consumption (propositions even now not fully tested); or the practices may have had a fundamental philosophical rather than religious basis in respect for animal life, so minimising meat consumption. Beliefs, no matter how strongly they are apparently held, may not always or consistently be translated into action (Kouris et al. 1991). This lin1its the certainty of deductions about early food cultures from which the beliefs have been derived, but nevertheless tells something about the food culture of our ancestors (see also Chapter 3).

CRITICAL EVENTS IN HUMAN HISTORY AND FOOD INTAKE

Food intake has affected human history in profound ways (Wahlqvist 1992). These include:

1 ecological change 2 population size 3 war and conflict 4 migration 5 loss of indigenous cultures

Some specific examples are worthy of consideration.

The role of the potato in human history

In the eighteenth century Linnaeus counselled against the introduction of the potato as food into Sweden because of its potential toxicity, later confirmed when the neurotoxicity of solanene in green potatoes was appreciated. Linnaeus's concern proved correct in another way, because with the introduction of the potato, the Swedish population increased dramatically. Farms were able to produce many more calories of food per hectare than before and so larger families could be supported on the same farm. But the population expanded beyond food production capacity and, during the latter part of the nineteenth century, one-quarter of

millions

40

30

20

10

Chapter 1 Introduction to human nutrition • 7

the Swedish population-one million out of four million-emigrated, principally to North America. Similar impacts of potato production on human population were seen in the British Isles (Figure 1.1).

Perhaps one of the major influences of food on history was the transfer of the potato and of maize to Europe from Central America. Evidence points to these crop introductions to Europe as having led to a major population explosion and ultimately to the colonisation of the Americas, Australia and New Zealand by Europeans. Earliest evidence for the use of the potato comes from Central and South America, where it was represented in pottery as early as 200 AD and was probably cultivated for thousands of years. It appears to have become a strong part of food belief and culture, although not to have led to the same degree of population growth as in Europe. The sorts of checks and balances that operated in the Americas but not in Europe are unclear. We know well enough what a profound social effect the potato had on Europe. On account of the monoculture and susceptibility to plant disease, famine became a problem, most notably the Irish potato famine of 1845 and 1846. The potato was also fermented to provide an alcoholic beverage even when the food supply was short. During the years of World War 11, Britain still saw the potato as a preferred crop as it could be produced locally, reducing dependence on grains. One of the remarkable aspects of

acres

700

600

500

400

300

200

100

1770 80 90 1800 10 20 30 40 50 60 70 80 90 1900 10 20 30 40

Figure 1.1 Population growth (EFGHIJ) in England and Wales from 1770 to 1940 in relation to the introduction and

expanding acreage of potato as a crop (ABCD). During this time the acreage sown with wheat increased

to a much lesser extent (Salaman 1987)


the potato is the wide range of climates that it can tolerate. There is ongoing pressure to meet hunun food requirements, especially locally, by more and more successful potato production, despite the lessons of history. It was reported recently that Australian scientists have developed a 'hairy potato' which would alleviate food problems through greater disease resistance.

Seafaring, exploration and nutrient deficiency

Not only did increased food production stimulate migration as a consequence of population growth, but the very ability to travel long distances depended on the resolution of problems of human nutrition. The classic example of this was the recognition that scurvy was a nutrient deficiency disease among seafarers. Scurvy had been identified by the Egyptians and reference to it appears in the Papyrus Ebers about 50 BC. About 600 BC Hippocrates described what was probably scurvy among the Greeks, and Pliny described the condition among the Romans in 63 AD. An account of scurvy is given in the first edition of the Encyclopaedia Britannica in 1771. A report published in Leiden in 1734 by J.F. Bachstrom maintained that the cause of scurvy was a lack of fresh vegetables or greens in the diet. The prevention of scurvy among the crew of Captain James Cook aided his discovery of Australia, yet the first European settlement at Sydney Cove was bedevilled by scurvy. When planted crops and trees failed, the use of Australian bush food helped to reduce the problem. Although James Lind had discovered the effects of citrus fruit in preventing scurvy on the ship Salisbury in 17 4 7, his treatise was not published until 1764 and the British Admiralty did not adopt his recommendations until 1795. Thereafter, British sailors were nicknamed 'Limeys' for their use oflimes and lime

juice to prevent scurvy. The major food problem that arose from relocated populations was that they tended to maintain a dependence on foods imported from their point of origin. Only slowly did locally grown foods take over in terms of cost-effectiveness.

Early European settlement in Australia

The countries to which Europeans migrated lost a good deal of their indigenous food culture and knowledge. The early immigrants had little insight into the value of local plant species and food culture for their own survival and health-let alone the ultimate value of a wider selection of foods for the survival of the human species as a whole. A major consequence of colonisation was deforestation and the turning of more and more of the new land to grazing for meat production and to grain production. By the beginning of the twentieth century, Australians had the highest per capita consumption of meat in the world, some 120 kg per head per year, followed by the USA, 68 kg, England, 45 kg, France, 34 kg and Germany, 29 kg. Australia has since dropped down the international league of meat consumption, the lead now being taken by Argentinians with Australia ranking about fourth or fifth. The fattiness of our meat supply is also undergoing a revolution towards leanness, and there appears to be significant associated change in the rates of diseases, such as coronary disease, that is likely to be related to the reduction in fat intake. It has taken 200 years to identify and correct this particular nutrition-related health problem. of European settlement in Australia.

It can be said that these historical events were, in general, long-term and unintended consequences of changes in human food acquisition, production, technology, trade and food preferences.

Chapter 4 The food supply • 39

THE AUSTRALIAN FOOD SYSTEM

The Australian food system is made up of 130 000 farmers, more than 3500 food manufacturers, a large number of supermarkets (most controlled by two major chains), plus many other retailers, convenience stores, fast food outlets, restaurants, and nearly 19 million consumers. Some $33 billion is spent on food each year and processed food exports are worth more than $10 billion. Figure 4.3 depicts the interrelationships in a modern food system.

The food industry has three organisational levels:

primary production, concerned with the growing of plant and animal foodstuffs on farms or harvesting of fish and seafood;

2 food processing, concerned with off-farm activities employing technology to modifY the primary produce into recognisable items of food (such as processing pigs into ham, or wheat into bread or pasta);

3 retail food industries, responsible for the distribution and sale of food products.

40 • Part 11 Contemporary food use and safety

\

Grain growers

Fertiliser/pesticide manufacturers

Agricultural machinery

\\ Petrol/diesel

\ '"''' Banks

finance/loans

Fruit and vegetable

& restaurants

Some others not shown: • Electricity supply • Irrigation water supply • Road maintenance • insurance

Figure 4.3 Modern food system (simplified)

Cattle and sheep farmers

Dairy farmers

companies

Storage industry (e.g. fruit coolstores)

Abattoirs Meat processors

Milk processors (milk, cheese, butter)

EXPORTS

IMPORTS--

Supermarkets

/ CONSUMERS

PRIMARY PRODUCTION

The primary production sector employed an estimated 311 000 Australians in 1998-99 (ABS 1999). Most were engaged in the production of cereal grains, sheep, cattle and pigs, while a small proportion were involved in horticulture, fishing and the poultry industry. An indication of the value of primary production is given in Table 4.2.

The dollar value of primary production varies from year to year depending on weather conditions, and because much of our primary production is exported (for example, 40% of meat production), the income to farmers is also affected by the world export prices and the value of the Australian dollar against other currencies. For example, the 1989-90 value of primary industry in Australia was $16 000 million, whereas in the following year it decreased to $12 000 million (25% less), due to lower world commodity prices.

FOOD PROCESSING

The food processing industry adds further economic value to the products of agricultural production through processing operations that preserve food and increase product diversity. A major change in food supply throughout this century has been the steady increase in the use of industry-prepared foods. At the village stage of development food was prepared for cooking within the home. This would involve grinding

Table 4.2 Primary products of the Australian food system

Farming type Primary produce Product type


of grains, killing and cleaning of animals for meat, and digging or collection of vegetables and fruit. With the development of technologies, nwst of this food preparation has moved from the home to industry. Of course many food industries have been in existence for 2000 years or more, including flour mills, bakeries, butcheries, dairies and wineries. Food industries appearing through the eighteenth and nineteenth centuries included specialised factories for the production of biscuits, smallgoods, canned fruits and vegetables, soups, jams, confectionery, etc. During the twentieth century, food manufacturing companies have become steadily larger, taking over smaller companies and broadening their range of products.

It is useful at this point to note that the food industry is a free-enterprise system which depends for its existence on profitability. Any business that is not profitable cannot continue to operate, and therefore all business activities are directed towards competitive advantage. All new developments in the food industry (new foods, new marketing strategies) are a direct result of companies seeking competitive advantage. Major food companies have usually grown by buying other businesses that they see have good products and are successful. Some of these companies are very large and span a wide range of products.

Food processing is the largest manufacturing industry in Australia, employing around 3% of the workforce. The processed food industry accounted for $12.1 billion of food exports in 1998-99; 13.4% of total exports. Australia also imports foods and beverages

Annual production (A$ million)

broad acre meat

cereals

beef, veal, mutton, lamb, pigmeat

wheat, barley, oats, maize, rice

6229

5785

777

dairy

horticulture

fishing

other

Source: ABS 1999

oil seeds

grain/legumes

milk

fruit

vegetables

nuts

honey

seafood

poultry

rapeseed (canola), sunflower, cottonseed, soy

lupins, soy 512

liquid milk, manufacturing milk (for butter, milk powder and cheese) 2899

stone fruits (e.g. peaches), pome fruits (apples, pears), citrus fruit,) and others 4818

potatoes, tomatoes, onions, carrots, brassicas, peas, beans

peanuts, almonds, macadamias

fish, prawns, lobster, etc.

poultry, meat and eggs

32

Data not available

1335


(wines, cheese, confectionery, and so on) but exports exceeded imports by $7.7 billion, providing a valuable trade surplus. This sector is also a significant employer of labour; overall, in 1997-98 there were 3939 manufacturing establishments in the processed food and beverage industry which employed a total of 167 774 people and had a turnover of $46.6 billion (Agriculture Fisheries and Forests-Australia 2001). In purely monetary terms the processed food industry is twice as large as the agricultural industry and many processing businesses are located in non-metropolitan regions where they make a significant contribution to the economies of inland areas. The two largest employers in country areas are the meat processing and bakery industries. Overall, the industry is highly concentrated with 60% of the market share being in the hands of only 20 companies. Some like Unilever, Nestle, and Phillip Morris are multinational giants whose annual turnover in 1992 was in the region of US$40-60 billion each (Tansy and Worsley 1995). The major food processing industries and their product type are listed in Table 4.3.

Goodman Fielder is Australia's largest food manufacturing company with sales revenue of over $1 billion in Australia, and over $3 billion in total, exporting food products to 40 countries. It handles grain products, bakeries, fruit and vegetable processing, meat products and many others in 120 manufacturing facilities in Australia and New Zealand. It is the country's largest miller and baker, producing breads and baked goods under twelve main brands. One of the divisions, Meadow Lea Foods, produces margarine, cooking oils, sauces, Asian and Indian prepared foods under sixteen different brands. It also produces various

brands specifically for individual supermarkets. The company spends $25 million a year on research and development in endeavouring to keep ahead of its rivals and introduces a broad range of new products each year. Many of these are currently aimed at the 'health' market which is seen as a growth sector. Examples are Healthwise cereals, Organic VitaBrits, Logicol cholesterol lowering margarine, and Lite Chips. The company sees a profitable future in ready-prepared foods, bringing Asia@Home ready-prepared meals and Top Nosh chilled meals onto the market (Goodman Fielder 2000).

RETAIL: SHOPS, SUPERMARKETS AND MARKETING

The sector of the food system that focuses on selling food to consumers is the retail food industry. Prior to 1950, foods were bought from a small number of specialised food shops. These included the grocer (packaged, dry and canned foods), greengrocer (fruit and vegetables), baker, butcher, milk bar/ confectionery shop. A large grocery store would have stocked several hundred products, most of these being constituents which would be used in the home to make complete meals. The composition of most of the food products was obvious to the purchaser (for example, flour, sugar, butter), thus not requiring detailed food labelling. Nutritional advice could at that time be given in terms of the five food groups (cereals and cereal products, meats, milk and milk products, vegetables and fruits). During the 1960s, supermarkets began to appear in Australia. The supermarket system brought in self-

Table 4.3 Major food processing industries (by product type)

alcoholic beverages (beer wine, spirits)

cereal and baked products (pasta, breakfast cereals, bread, pastries)

confectionery products (chocolate, lollies)

dairy products (cheese, milk, yoghurts, ice-cream)

dessert products (mousse, toppings, custard)

eggs and egg products (batters, cake mixes)

fat based products (butter, margarine)

fermented food (salamis, pickles, soy sauce)

fish products (fish sticks, processed seafood meats)

flavouring products (spices, herbs, sweeteners)

food analogues (textured soy products)

fruit and fruit products (canned fruit, juices)

functional foods (various products)

jams, jellies and related products

meats

soft drinks (cordials, carbonated drinks)

sugars and related products (treacle, honey, syrups, granulated sugar)

vegetable and vegetable products (canned and frozen vegetables)

servKe, doing away with the old system of each customer being served from behind a counter. This reduced the requirement for paid staff and therefore reduced costs for the supermarket. This cost saving was passed on, in part, to the consumer in the form oflower food prices which, in turn, attracted more customers and increased market share for the supermarket. Most of the small grocery stores were forced out of business.

Numerous other labour-saving devices have been introduced over time to cut costs. One outstanding example is bar-code identification of individual products and the linking of this to checkout registers and computer stock management, introduced in the early 1980s. Bar-coding reduced markedly the amount of staff time required to process payment for goods selected, and additionally, did away with the need to put price labels on foods. Bar-coding also enabled computer auditing of sales and automatic ordering of supplies from the wholesale warehouse; again saving staff labour and reducing costs.

Most food retailing is now controlled by supermarkets which are spacious, allowing room for many more food products. Food processing companies, keen to expand their businesses, have employed food technologists to develop an ever increasing range of new products. The forces driving the increase in variety of products include:

the endeavour to increase sales and maximise profits by both the food manufacturer and supermarket;

2 the attraction to consumers of products with a wider variety of tastes and textures;

3 a preference of consumers for foods which need less time and work in preparation (due in significant degree to more homemakers being in full-time employment).

A modern supermarket may stock 20 000 to 30 000 different items. This increase in the variety of foods on sale and the increased complexity of food formulations has resulted in the composition of foods being less obvious to the consumer. Whereas the five food groups were generally fairly well understood, many of the more complex food products do not fit the food groups and their composition is not obvious. Prepared desserts, pasta sauces, highly flavoured snack foods, and toasted muesli are examples of complex manufactured foods with compositions which are not obvious from


appearance or taste. As a result, ingredient lists on food labels and nutrition panels on the packaging of food products have become a necessity for the consumer who wants to know what is in the food.

In Australia, approximately two-thirds of food retailing is controlled by two supermarket chains. These two companies, Woolworths and Coles Myer, wield enormous power in the food industry. Coles Myer, which employs around 170 000 staff in over 2000 stores, operates a number of different types of retail outlets, of which Coles and Bi-Lo make up the supermarket division (Coles Myer 2000). Woolworths, which operates 1114 stores across Australia, is concentrated more on food and owns the Woolworths and Safeway supermarkets, Purity and Roelf Vos supermarkets, Food For Less and a number of alcoholic beverage outlets with total annual sales of about $8.4 billion (Woolworths 2000). Because the maJor supermarkets are so large they can buy food products in amounts as large as hundreds of tonnes at a time. Manufacturers compete eagerly for such large contracts and therefore offer the lowest prices that they can manage. This maintains a competitive advantage for the major supermarkets because they can afford to undercut the prices of smaller stores. The major supermarkets also offer their own 'house' brands-in the case of Coles Myer, the Farmland, Savings and Coles labels. These are produced and specially branded for Coles Myer by large manufacturers. These brands are often priced lower than competing brands to keep customers coming back to that supermarket chain.

If a manufacturer brings a new product to the supermarket, the supermarket can demand that the manufacturer spends a large amount on advertising to ensure that the product has satisfactory sales. If sales are not adequate the supermarket will decline to stock the item which ensures that that food product will no longer be available. New products are continually being tried; some succeeding and many failing. The key figure for the supermarket is sales and profit per unit area of shelf space, though profit margins vary across different products. Standard items such as milk, bread and potatoes have relatively small margins compared to 'luxury items' such as confectionery and snack foods. It is in the supermarket's interest to offer good quality and price on standard items to bring customers back and then tempt them to buy the luxury items while they are there. The layout of the supermarket is designed to achieve this. Milk, margarine, cheese, bread, meat,


vegetables and fruit are dispersed around the perimeter of the supermarket while the luxury items are in the centre or placed close to the checkout to encourage impulse buying.

Approximately ten years ago Woolworths established its 'fresh food' initiative, bringing a much larger selection of fruits and vegetables into the supermarket in a brightly lit display. This was hugely successful and has now been copied by competing supermarkets. Woolworths achieved a doubling of turnover between 1986/87 and 1993/94, from $4.6 billion to $9.8 billion, due in part to a 300% rise in fresh food sales. Fresh food now accounts for 40% of sales in Woolworths supermarkets (Shoebridge 1993).

Some years ago 'convenience stores' established a niche market with small stores which stayed open for extended hours; opening early in the morning and closing late at night. Sometime later, changes in State law enabled supermarkets to remain open for 24 hours and the extended hours advantage of the convenience stores was eroded. Woolworths has established selling of petrol at many of its supermarkets as an added attraction. In response two major petrol companies have established convenience food stores at their service stations. These changes illustrate the fiercely competitive nature of the retail industry.

THE ROLE OF GOVERNMENT

The activities of Commonwealth, State and local governments have a significant impact on the food system, affecting not only local production and consumption, but also imports and exports. Governments set policies, regulations, levels of taxation, standards and requirements that can either stimulate or inhibit food businesses. Table 4.4 shows some of the Commonwealth Government's impacts on the food system in Australia.

NEW FOOD PRODUCTS

It is interesting to consider how the food supply changes; the public will not buy a new product if it is not available on the shelf, and the supermarket will not stock a new product if they are not reasonably certain that it will gain satisfactory sales. Usually the food manufacturer carries the risk; trying a new product after experimental formulation and testing with taste

panels. Successful development of a new product can be very profitable for the food manufacturer. Over the last 10-20 years many new 'healthy' foods have appeared in supermarkets; a number of these are listed in Table 4.5.

As in clothing, there are strong 'fashions' in food, and manufacturers and supermarkets provide products to fulfil the requirements of fashion-conscious customers. 'Health foods' appear to be affected as much by fashion as other foods. A few years ago very low alcohol beer appeared in supermarkets (less than 1% alcohol) but sales were poor so it was withdrawn. High fibre foods became fashionable for health reasons and oat bran became particularly fashionable as a 'cholesterol cure' but more recently interest has waned. Currently olive oil is near a peak in popularity.

In terms of 'healthy' foods, the question of salt content is interesting because it shows up the problem of conflict between winning customers and providing a product that is nutritionally as good as can be made. There is evidence that excessive salt intake over a period of years is likely to lead to high blood pressure (hypertension) in susceptible people. As manufactured and convenience foods become more popular, a higher proportion offood energy intake is obtained from these foods. Manufacturers compete to gain market share, and in doing so they conduct taste tests to find the food flavour and texture that is most attractive to their customers. By doing this they aim to bring their customers back regularly to buy their products. The level of salt in food which is most attractive to taste is generally between 1% and 2%. Flavouring foods with salt at the level most attractive to taste is likely to lead to excessive consumption of salt if manufactured foods make up a high proportion of total food intake. This creates a problem for the manufacturer: keep salt high and retain customers, or decrease salt and risk losing customers? A number of companies have responded by bringing both the normally flavoured and a reduced salt product onto the market, thus allowing the customer to make the choice.

The market for food is 'inelastic' (not expandable) in the sense that the total amount of food sold each year remains fairly constant because people can only eat a certain amount. In contrast, the demand for new cars would be said to be 'elastic' because the individual can choose whether or not to buy. Because the demand for food is inelastic, growth in revenue and profit can only be achieved by taking market share from other companies, developing new products with a value-

Table 4.4 Some Commonwealth Government impacts on the food chain, and the departments involved

Farm

Regulation of:

Agricultural chemical use Veterinary chemical use

Examples of responsible government agency

National Registration Authority (Dept of Agriculture, Fisheries and Forestry)

Environmental protection Environment Australia (Dept of Environment and Heritage)

Food industry

Competition

Food contaminants/ additives


Australian Competition and Consumer Commission (Dept of Treasury)

Australia New Zealand Food Authority (Dept of Health and Aged Care)

Environmental protection Environment Australia (Dept of Environment and Heritage)

Provision of:

Research funding Rural Industry Research Research funding and Development Corporation (Dept of Agriculture, Fisheries and Forestry)

Universities; research institutes; CSIRO (Dept of Industry, Science and Resources)

Policy advice and support Australian Bureau of Policy advice and support Australian Trade Agricultural and Resource Economics (Dept of Agriculture, Fisheries and Forestry)

Monitoring and support services for industry:

Facilitating the export of primary produce

Business support:

Tax breaks and other incentives

Australian Quarantine and Inspection Service (Dept of Agriculture, Fisheries and Forestry)

Ensuring safety of food exports and imports

New Industries Development Business financial Program (Dept of support, loans and Agriculture, Fisheries and insurance Forestry) Australian Taxation Office (Dept of Treasury)

Source: Commonwealth Government websites Note: the food system is also affected by the actions of State Governments; not shown here

Commission: Austrade (Dept of Foreign Affairs and Trade)

Australian Quarantine and Inspection Service (Dept of Agriculture, Fisheries and Forestry)

Policy and quality monitoring

Australian Trade Commission (Austrade); Export Finance and Insurance Corporation (Dept of Foreign Affairs and Trade)

Consumers


Ensuring food quality and Australia New Zealand Food providing food information Authority (Dept of Health and

Aged Care)

Ensuring fair prices

Public health monitoring Australian National Residue Survey

Australian Competition and Consumer Commission (Dept of Treasury)

Dept of Health and Aged Care, National Office of Food Saftey (Dept of Agriculture, Fisheries and Forestry)

Consumer Affairs (Dept of Treasury)


Table 4.5 Health-marketed foods in supermarkets

reduced fat milk

reduced fat cream

reduced fat margarine

high P:S ratio margarine

low fat minced meat

low fat cheese

yoghurt ice-cream

bread with added folate

breakfast cereal with vitamins and iron

low calorie soft drinks

artificial sweeteners

jam with artificial sweetener

low cholesterol cheese substitute

low sugar (diabetic) chocolate

sweets with artificial sweetener

low alcohol beer

high fibre bread

oat bran

low salt butter and margarine yoghurt with probiotic culture

vitamin supplements

mineral supplements

'sports' bars

'sports' drinks

added component (such as ready-prepared meals) or marketing foods with a higher price and higher profit margin. We would not expect that Goodman Fielder would increase its profits significantly by bringing another brand of ordinary margarine onto the market but Logical ($16.76 per kg at the time of writing) sells at a premium to their existing brands (approximately $4 per kg) and we might expect that the price incorporates a higher profit margin. In contrast, Coles Supermarket's own 'house' brand sells for approximately $3 per kg.

Logical is an example of a new type of product called 'functional foods' which are claimed to have benefits greater than just the provision of nutrients. They contain components (whether nutrients or not) that affect one or more targeted functions in the body in a positive way (Diplock et al. 1999). Logicol is one of a group of margarines with added plant sterols that when eaten as part of a no~mal diet reduce the absorption of cholesterol, thereby reducing the level of blood cholesterol and the risk of atherosclerosis and heart disease. It can reduce blood cholesterol levels by a significant amount, especially in middle-aged men. Another functional food is a bread manufactured by George Weston Foods Ltd, called Burgen Soy-Lin, containing phytoestrogens and claiming to reduce symptoms associated with menopause in women Qorgensen et al. 1998). The production of functional foods with marketing targeted at the health-conscious consumer has grown into a large industry with a world market value estimated at US$17 billion in 2000.

Advertising of functional foods in Australia and New Zealand is restricted by current legislation that prohibits claims relating to health or disease. However this regulation is currently under review and it is anticipated that health claims will be allowed in the near future as they are in other countries such as the United States (see also Chapter 9).

CONVENIENCE FOODS-BUILDING SERVICES INTO FOODS

The increased efficiency in the growing, manufacturing and marketing of foods has resulted in food being significantly cheaper to the consumer. It should be noted here that the cost of food has to be thought of in 'inflation adjusted' terms. It used to be that a worker would need to spend 60-80% of earnings on food for a family whereas now the equivalent expenditure is more like 20-30% of earnings spent on food.

Customers do not necessarily purchase cheaper food. Convenience foods are often chosen in preference to cheaper foods which require more time to prepare. Many convenience foods require only opening of the packaging, followed by heating and serving. In such cases the consumer is choosing to pay for the convenience of having the food prepared ready for use; or, in other words, the consumer is paying for a service built into the food product.

The most recent initiative is the push to sell fully prepared meals, either hot and ready to eat or simply requiring heating and serving. Of course, ready-to-eat foods have always been available in one form or another, but the volume of ready-to-eat meals for consumption in the home is steadily increasing and supermarkets estimate that this product line is the one likely to show the fastest rise over the next few years. The chilled and frozen food sections in supermarkets are steadily expanding. Goodman Fielder's 'Top Nosh' ready-prepared 'restaurant-quality' meals, for example, incorporate the service of meal preparation and, at the time of writing are priced ($5.98 for a 380 g single serve) at about half of what a customer might expect to pay in an inexpensive restaurant. Of course the ingredients are relatively cheap but the company has built added value into the completed meal so realising a higher price and profit margin.

SNACK FOODS AND FAST FOODS

Snack foods are those commonly purchased for eating outside the normal pattern of meals. The group is not easy to define because of the large range of foods which fits the description. Typical of the group are potato crisps and chips, pies, pasties, hot dogs, confectionery bars and soft drinks. Many factors underlie the increased use of snack foods. These include:

• increased wealth (purchasing power) • increased leisure time • increased mobility (personal transport, more time

away from home) • newer technologies for creating foods with highly

attractive tastes and textures • development of large scale manufacturing,

enabling low cost

There is a blurring of distinction between snack food, fast foods and restaurant meals as eating away from home has become more common. Fast foods, defined as hot ready-to-eat foods purchased at a convenience outlet, may be eaten while travelling or at a sports event, or at the site of purchase which is then a restaurant. Or they may be delivered to the home to substitute for a home-cooked meal. In addition, these same foods may be purchased chilled or frozen at the supermarket, so it is becoming increasingly difficult to categorise foods.

MODERN MARKETING AND ADVERTISING

Modern marketing techniques, of which advertising is the most prominent component, have a strong influence .on food choice. By a more subtle mechanism, marketing also affects food availability. Advertising is so pervasive that its presence merges into the city landscape. Shopfronts and advertising billboards carry advertisements for foods in almost every commercial street. Television is a major avenue of exposure. The fact that manufacturers spend large amounts of money on advertising shows that market research has proved its importance to sales and profits. Table 4.6 shows the

Chapter 4 The food supply • 4 7

Table 4.6 Amount of money spent on advertising food and other products in Australia, 1997

Food (or other item) Amount spent per year($ millions)

aerated soft drinks 39

alcoholic beverages 67

bread 10

breakfast foods 55

cheese 16.5

confectionery 59

snacks

Comparison items

cars

pet food

analgaesics

Source: Ad News 1997

19

444

22

23

amount of money spent on advertising several food products in Australia in 1997.

To put the figures in context, the annual spending in the soft drink grocery market in 1997 was about $873 million. Soft drinks have a relatively low cost of production and much of the retail price is made up of marketing costs and profit margins. Although we are influenced by advertising and we are aware of it in our daily surroundings, we tend not to be aware of its influence on our own purchases.

Food, entertainment and eating out

A remarkable change in Australian food habits in recent years has been the rise in eating away from home. The number of restaurants, food bars, and other outlets selling 'ready-to-eat' food has multiplied manyfold over the last 40 years. Increasing wealth, increased leisure time, an increase in the number of cultures represented in the food trade, and fashions in leisure time entertainment are probably all partly responsible. The extent of the 'eating out' industry is shown by the rapid expansion in the number of restaurants over recent years. The nutritional quality of the food offered varies widely from excellent to excessively fatty and salty. There is no clear indication of the effect of dining away from home on nutritional status. There are indications that Australians on average are becoming fatter, but how much this relates to changes in the food supply is not known.

New and emerging developments food production

. 1n

David R. Briggs and Louise B. Lennard

OBJECTIVES

• To understand how the composition of food is modified to meet particular dietary requirements.

• To introduce a number of naturally occurring biologically active substances used in functional foods.

• To understand the concept and role of 'functional foods'.

• To introduce the concept and role of genetically modified foods.

• To understand the role of biotechnology in producing foods, ingredients and food additives.

• To learn how new food processing technologies are used.

INTRODUCTION

Other chapters in this book discuss in detail nutrients and other biologically active components of food such as contaminants and micro-organisms. In this chapter we explore some recent developments in food technology including 'functional foods' which have been specially tailored to offer improved nutritional or other health benefits to the consumer. This chapter does not intend to provide an exhaustive list of food technologies currently in use, but rather to offer a sample offuture directions (see Figure 8.1).

Food processing in various forms has been carried out for many centuries. Examples of traditional methods of food processing include salting, smoking, dehydration, canning and freezing of food and are discussed in Chapter 5. Recent improvements in traditional forms of food processing have included the production of traditional and new food ingredients and components from biotechnology and the development of improved packaging materials. Recent developments in food technologies have enabled the production of some foods with improved nutritional value, organoleptic properties (colour, texture, flavour), convenience and lower cost. Advances in the food industry also include efforts to develop sustainable agricultural practices and to develop

115

116 Ill Part 11 Contemporary food use and safety

selectively decrease the concentration of component in source food {biotechnology)

extract component from source food {e.g. supercritical fluid extraction, ultra-filtration, reverse osmosis)

synthesise component {e.g. fermentation, use of genetically modified

organisms, planttissue culture)

selectively increase the concentration of component in

source food {biotechnology)

\I add biologically active component to food,

'functional food'

decrease consumption of biologically

active component

increase consumption of biologically

active component

consumption of diet beneficial to health

,..-----------{/ modify food, develop

foods which meet special dietary needs

{e.g. reduced fat foods, low energy foods, gluten free foods)

\')------_ develop foods with sensory appeal {e.g. biotechnologydelayed softening tomato;

minimal processing methods; recent processing methods:

modified atmosphere packaging)

Figure 8.1 The application of recent technologies to food production

environmentally friendly packaging materials while still retaining the essential characteristics of the food and ensuring that it is microbiologically and chemically safe. 'Functional foods' are expected to be an important development for the food industry and promise to improve health or reduce the risk of diet-related disease by offering foods with either an increased or reduced level of biologically active components.

FUNCTIONAL FOODS

In the past, nutritional quality generally related to the level of macronutrients (protein, carbohydrate, lipids)

and micronutrients (vitamins and minerals) in a food. More recent research into the composition of food has revealed the presence of many other biologically active substances which may be important for health, for example dietary fibre and phytochcmicals. Foods of the future are likely to include so-called 'functional foods' where biologically active substances arc either increased or reduced in order to offer the consumer the potential benefit of enhancing their health or reducing the risk of disease. The US Institute of Medicine's Food and Nutrition Doard in 1994 defined a functional food as 'any food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains'. Recently, the European division of the International

Chapter 8 New and emerging developments in food production Ill 117

Life Sciences Institute (ILSI) defined a functional food as a food that 'can be a natural food, a food with a component added, or a food with a component removed by technological or biotechnological means' (Diplock et al. 1999). Terms used synonymously with functional food include' designer foods', 'medical foods' and 'nutraceuticals'.

Functional foods originated in Japan in the mid 1980s. In Japan, functional foods are described as Foods for Specified Health Use or FOSHU, and are a subclass of Foods for Special Dietary Uses. Of the one hundred foods licensed as FOSHU, most contain either oligosaccharides or lactic acid bacteria for promoting intestinal health.

Recently the Australia New Zealand Food Authority (ANZFA) introduced legislation for 'Novel Foods'. Novel foods are defined as non-traditional foods which do not have a history of significant human consumption by the broad community in Australia or New Zealand and which have features or characteristics which require special attention with respect to their safety. Foods which are expected to be classified under the novel foods standard include dietary macrocomponents, extracts of plants, animals or microorganisms, single ingredient foods and viable microorganisms. Novel foods must be approved by ANZFA prior to sale in Australia and New Zealand. (Likewise, genetically modified foods and irradiated foods must also be approved on a case-by-case basis by ANZFA prior to sale) (ANZFA 2000a).

Examples of products which the food industry may wish to promote as functional foods in the future (if future food laws permit claims about their health benefits) may include foods with functional ingredients added, for exam.ple micro-organisms (see Table 8.1). Other examples may include food with a changed physico-chemistry thereby altering its digestion and/ or absorption; fortification of foods with micro-nutrients in excess of Recommended Dietary Intakes (RDis) or with non-nutrient food constituents that have physiological effects such as the class of chemicals known as flavonoids. Recent developments m functional foods in Australia include the availability of eggs with increased levels of omega-3 fatty acids as a result of adjusting feeds given to chickens and the availability of ferm.ented dairy products containing live bacterial cultures (probiotics). Some fermented dairy products are pasteurised after production and thus contain significantly lower concentrations of live

bacteria. Further research is required to assess the safety and bioavailability of consuming large quantities of biologically active components in foods (for example flavonoids) and to understand the effects of processing on beneficial bioactive substances. Biological markers of biologically active substances in food are important to identifY potential benefits or risks of these components, for example an increased level of red blood cell folate is indicative of the dietary intake of folate. Concerns about the use of functional foods have been raised by many consumer organisations and public health professionals, focusing particularly on the potential of functional foods to distort the selection of a healthy, balanced diet by 'medicalising' food. Table 8.1 lists some proposed and commercially available functional foods.

Nutrient-supplemented functional foods

Many functional foods currently available are foods which have been fortified or supplemented with nutrients. For example, some infant foods available in Northern China (where exposure to sunlight may be restricted during winter months) are fortified with vitamin D in order to prevent rickets in the population at risk. A recent development in Australia has been the provision in the Australia New Zealand Food Standards Code to permit folate fortification of foods (in turn consumed by women of child-bearing age) as part of a public health strategy to minimise the development of neural tube defects in the fetus (NHRMC 1994).

Functional foods with modified composition

Many functional foods are specifically formulated to meet a particular dietary requirement such as gluten-free foods for people with coeliac disease, low energy foods for people consuming reduced-energy diets, carbohydrate modified foods for people with diabetes and lactose-free foods for people with lactose intolerance. Public health policies aim. to improve the health of citizens and reduce the risk of disease. In Australia, the Dietary Guidelines for Australians (see Chapter 38) list measures for consumers to adopt in order to improve their health and lower their risk of developing chronic diseases. One of the guidelines advises the consumption of a diet which is low in fat and, in particular, low in saturated fat. Foods which are developed to offer consumers a choice when selecting an appropriate diet must retain their appeal and offer


Table 8.1 Examples of functional foods

Type of functional food Examples of functional foods Description ------~--------------------------~-----------------------------

increased level of a biologically active substance

decreased level of a biologically active substance

other modifications

nutrient enriched foods e.g. folate for women of child-bearing age, in particular, to help enrichment prevent the development of neural tube defects in

the fetus, to decrease levels of plasma homocysteine

omega-3 fatty acid enriched eggs

foods enriched with phytochemicals

phytosterol/phytostanol enriched foods

foods enriched with resistant starch, non-starch polysaccharides and polyols

foods with added resistant starch

electrolyte drinks

creatine enriched sports foods

foods with probiotics and/or prebiotics

foods with bioactive peptides

foods with added caffeine

infant formulas with added colostral immunoglobulins and lactoferrin

foods with increased thermogenic potential

(a risk factor for cardiovascular disease)

chickens fed fish meal to increase EPA and DHA in eggs

to increase the antioxidant content of a food, e.g. lycopene, flavonoids, isoflavonoids

enriched margarine to reduce total plasma cholesterol levels

to lower blood glucose levels

to increase fermentable substrate for colonic bacteria, e.g. breads

isotonic drinks with carbohydrate, fluids for use during sport

to enhance physical performance by decreasing the formation of lactic acid and ammonia

probiotic cultures such as Lactobacillus acidophilus, Bifidobacterium bifidus in yoghurt, fermented milk drinks; prebiotic components such as inulin and other fructooligosaccharides

fermented milks containing angiotensin I converting enzyme inhibitors to reduce hypertension, opioid activity (exorphins), immunomodulatory activity (stimulating lymphocytes and macrophages)

to improve mental alertness

to improve infant immunity against infection by including biologically active substances present in breastmilk

with caffeine, gingerols, shogaols, capsaicinoids, to assist with reducing obesity and maintenance of body weight

fine rice (Japan) with decreased globulin for people with allergic dermatoid atopy (see content Chapter 33)

hypoallergenic foods

low phosphate milk (Japan) with decreased phosphorus, calcium and sodium

low cariogenic confectionery, replacing sucrose with oligosaccharides and resistant starch

gluten-free foods

lactose-free foods

fat modified foods

low glycaemic index foods

hypoallergenic cow's milk infant formulas containing hydrolysed proteins

for people with chronic kidney disease

to reduce the incidence of dental caries (tooth decay)

for people with coeliac disease and dermatitis herpetiformis (see Chapter 33)

for people with lactase deficiency (see Chapter 33)

reduced fat foods, fat free foods, foods containing fat replacers (e.g. Olestra), fats with altered fatty acid composition

to reduce plasma glucose, decrease insulin resistance

Chapter 8 New and emerging developments in food production • 119

Type of natural functional food (American Dietetic Association 1999) Examples of functional foods

vegetables and fruit broccoli black or green tea fish beef, lamb, dairy foods tomato products carrots soy foods and products garlic oat products grapes and grape juice, red wine Jerusalem artichokes, chicory root, bananas, garlic

enjoyment or they will not be consumed-food offers more than simple nourishment. The need for a low or reduced fat content, for example, requires developing foods which retain their organoleptic and physical properties, and therefore their appeal. There is some evidence that we are born with an innate preference for sweet foods. Similarly, pleasure responses have been measured for high fat foods and may involve central brain mechanisms-serotonin and opioid peptides may mediate preferences for carbohydrates, fat and sugar.

Reduced fat foods

In Australia, low fat foods must contain less than 3 g fat per 100 g or less than 1.5 g fat per 100 g if the food is a liquid. Foods labelled as being reduced in fat must have a reduction of at least 25% of the total fat content compared with the same quantity of the reference food and an absolute reduction of at least 3 g fat per 100 g of food (or a reduction of 1.5 g fat per 100 g of liquid food) (NFA 1995). The challenge for the food technologist is to remove the fat, particularly saturated fat, without decreasing the functionality or organoleptic appeal of the food. Reduced fat foods are formulated using ingredients low or reduced in fat and adding other ingredients to replace the functional roles of fat. Fat has an important role in food as the solvent for fat-soluble vitamins, essential fatty acids and flavour compounds and contributes significantly to the mouthfeel of a product. Fat replacers generally aim to mimic the mouthfeel and texture of fat (see Table 8.2). The fatty acid composition of a food influences the physical characteristics of that food. Fats with a greater proportion

Biologically active substance

vitamins, phytochemicals, dietary fibre sulphoraphane catechins (flavonoids) omega-3 fatty acids conjugated linoleic acid lycopene beta-carotene soy protein organosulfur compounds beta-glucan soluble fibre phenols and resveratrol fructooligosaccharides (inulin)

of saturated fatty acids are more solid at room temperature and are less susceptible to oxidation than fats comprised of unsaturated fatty acids. Currently there is no single fat replacer that replaces all functional and sensory qualities of fat in food. However, combinations of fat replacers can achieve an acceptable reduced or low fat product. Further research is required to determine whether the use of fat replacers or the consumption of low and reduced fat foods will actually result in lower fat and energy intakes.

Low energy foods

'Low energy foods' are defined in the Australia New

Zealand Food Standards Code and are required to contain no greater than 170 kJ per 100 g of solid or semi-solid food and a maximum of 80 kJ per 100 mL for beverages and liquid foods. Other terms synonymous with 'low energy' include 'low joule' and 'low calorie'. Any claim that a food that is intrinsically low in energy must refer to the whole class of foods, for example, tea is a low joule food. 'Low energy foods' are formulated by paying attention to the energy value of the ingredients and where possible substituting lower energy ingredients for higher energy ingredients (see Table 8.3). For example, nutritive sweeteners such as sucrose can be replaced by the food additive sweeteners acesulphame potassium, alitame, aspartame, cyclamate, saccharin and sucralose (see Chapter 7). Care must be taken to find modifYing agents to replace the technical function of sugars in these foods. Sugar(s) not only impart sweetness to a food but function as a preservative (by lowering water activity) in jams,


Table 8.2 Examples of fat replacing ingredients

Carbohydrate-based fat replacers Protein-based fat replacers Fat-based fat replacers

• cellulose, ·microcrystalline cellulose: • for dairy products, salad dressings,

microparticulated protein: for dairy products, salad dressings

• emulsifiers: for cake mixes, biscuits, dairy products

sauces, frozen desserts • whey protein concentrate • fat analogues, potential future food additives yet to be approved for use in Australia (for example sucrose polyesters which are resistant to digestion)

• vegetable gums (for example xanthan, guar, locust bean, carrageenan): for salad dressings, processed meats

• inulin, pectin • dextrins (for example, from tapioca,

oats): for salad dressings, puddings, dairy products, frozen desserts

• maltodextrins (for example from corn): for baked goods, salad dressings, dairy products, sauces, frozen desserts

• modified starches (for example from corn): for salad dressings, baked goods, frozen desserts, dairy products

• polydextrose: for baked goods, confectionery, salad dressings, frozen desserts, puddings

Source: American Dietetic Association 1998

caramelise in baked goods, are hygroscopic (absorb moisture) to delay staling and texturise the crumb in baked goods, provide bulk and volume and act as a substrate for fermentation (Table 8.4).

Carbohydrate modified foods

Carbohydrate modified foods are formulated to replace sugars (monosaccharides and disaccharides) with sugar alcohols or polyols. The energy value of some sugar alcohols and polyols is similar to that of the monosaccharides and disaccharides. The difference is that the former are more slowly absorbed and therefore have less effect on blood glucose concentration.

• synthetic fats (for example, Caprenin [Procter & Gamble]. a triglyceride containing capric, caprylic and behenic acids: behenic acid is mostly unmetabolised and the other fatty acids are less efficiently metabolised resulting in an energy value of 21 kJjg compared to an energy value of 37 kJjg for regular fats; Salatrim [Pfizer]

Carbohydrate modified foods will probably play a lesser role for people with diabetes due to recent attention to the glycaemic index of foods (see Chapter 12). The cariogenicity of a food component refers to its ability to be fermented to acids, which may contribute to tooth decay. By replacing fermentable sugars such as the disaccharide sucrose in foods with non-fermentable carbohydrates such as sugar alcohols, oligosaccharides or resistant starch, it is possible to develop foods with a low or reduced canogenic potential, such as confectionery. However, it will still be important for consumers to continue to use good oral hygiene practices (Table 8.5).

Table 8.3 Reduced energy (kilojoule) substitutes for various components

High energy components

fat

sugars

alcohol

glucose syrups

starches

Source: ANZFA 2000a

Energy (kilojoules)

37 kJjg

17 kJjg

29 kJjg

17 kJjg

17 kJjg

Possible substitutes

maltodextrin

intense sweeteners

flavours

polydextrose

vegetable gums

Energy (kilojoules)

16 kJjg

negligible at levels used

negligible at levels used

5 kJjg

variable, depends on the vegetable gum and amount used

Chapter 8 New and emerging developments in food production 11 --------------------~ --- -·-··-· ------~-----------~---------- ----------- -

Table 8.4 Functional replacers for sugar

Function

Maillard browning

crystallisation

fermentability

humectant

hygroscopicity

Possible substitutes

maltodextrins, polydextrose

sorbitol, xylitol, lactitol, isomalt

maltodextrins, polydextrose

polydextrose

polydextrose, polyols, maltodextrins

viscosity, bulking agent polydextrose, vegetable gums

Gluten-free and low gluten foods

Gluten is a protein found in wheat, barley, rye, spelt and triticale, and possibly oats. People with coeliac disease must avoid gluten to prevent damage to their small intestine and those with dermatitis herpetiformis must avoid gluten to avoid skin lesions (see Chapter 33). Gluten-free foods can be form.ulated by using cereal grains where gluten has been removed or by substituting other non-gluten containing cereals for wheat, barley, oats, rye and triticale. Non-gluten containing cereals include rice, corn (maize), buckwheat and legumes (such as soy beans). Care must be taken to ensure all ingredients used are gluten free, particularly ensuring wheat starch has not been used as a 'carrier', such as for flavours (see Table 8.6).

Lactose-free foods

Lactose-free, low lactose and reduced lactose foods are specially developed for people with lactose intolerance (see Chapter 33). Products are formulated using ingredients that are lactose-free, for example soy protein isolates, and/ or ingredients where lactose has been wholly or partially removed. Fermented dairy products contain various levels of lactose as a result of

Table 8.5 Substitutes for mono- and disaccharides in carbohydrate modified foods

-----Mono- and disaccharides Sugar alcohols and polyols

sucrose lactose fructose glucose glucose syrups, starch hydrolysates, maltodextrin, invert sugar honey

glycerol maltitol and maltitol syrup isomalt lactitol

mannitol polydextrose, sorbitol, xylitol

Table 8.6 Requirements in Australia for gluten-free foods

Gluten-free foods Low gluten foods

must not contain detectable must not contain more than gluten and no oats or malt 20 mg gluten per 100 g of

food and have no oats or malt in the food

Source: ANZFA 2000a

fermentation of the lactose by lactic acid bacteria (Lactobacillus spp.) to lactic acid (see Table 8.7).

Probiotic and prebiotic foods

The gastrointestinal tract normally contains large numbers ofbacteria (natural microflora) including 107- 8

organisms in the oral cavity (predominantly Streptococcus, Veillonella, Neisseria), 102- 3 organisms in the stomach and small intestine (Lactobacillus, Streptococcus), and 1010- 11

organisms m the large intestine and colon (Bifidobacterium, Bacteroides, Eubacterium, Peptostreptococcus). Micro-organisms in the right side (proximal) of the colon grow at a fast rate due to a good supply of nutrients, resulting in short-chain fatty acid (SCFA) production thereby causing a decrease in pH. Shortchain fatty acids, in particular, butyrate, may have a beneficial effect on colonic cells in the human host. In contrast, in the left side (distal) colon bacteria grow more slowly due to a restricted supply of nutrients and therefore the pH often approaches neutrality.

Probiotics are viable micro-organisms which are beneficial to health by improving the intestinal microbial balance. In contrast, a prebiotic is a nondigestible component which beneficially affects the host by selectively stimulating the growth and/ or activity of one or a limited number of colonic bacteria, thereby improving the health of the host. The beneficial qualities of prebiotics include increasing faecal mass and/ or stool frequency and being a substrate for the

Table 8. 7 Requirements in Australia for low lactose and reduced lactose foods for specific dietary use*

Low lactose foods

Reduced lactose Lactose-free foods foods

-------------·- --------··----··----~----------------

must contain less must state the than 0.3 g lactose percentage of per 100 g of food lactose reduction

must not contain any detectable lactose

* the proportions of lactose and galactose must be declared in the nutrition information panel on the label

Source: ANZFA 2000a


synthesis of short-chain fatty acids. Synbiotic foods are mixtures of prebiotics and probiotics that beneficially affect the host by stimulating the growth or metabolism of health-promoting bacteria.

Foods metabolised by colonic bacteria include resistant starch and non-starch polysaccharides. By definition, these foods are classified as dietary fibre because they are not digested or absorbed in the small intestine (see Chapter 12). However, in order for a component to be classified as a prebiotic, it must satisfY the following criteria: a prebiotic must not be hydrolysed or absorbed in the upper gastrointestinal tract; it must be a substrate for growth or activity of one or a limited number of beneficial colonic bacteria; it must therefore be able to alter the colonic microflora towards a healthier composition and to induce luminal or systemic effects which are beneficial to the health of the host (Gibson and Roberfroid 1995). While many components of dietary fibre such as resistant starch and non-starch polysaccharides provide substrates for fermentation by colonic bacteria, fructooligosaccharides and galactooligosaccharides are the main types of prebiotics used in functional foods. Fructooligosaccharides are short- and medium-length chains of ~-D fructans and meet the criteria for prebiotics. Short-chains are referred to as oligofructose and medium-length chains are known as inulin. Foods containing oligofructose and inulin include garlic, onion, artichokes, asparagus, banana and garlic. Prebiotics may also inhibit the adherance of bacterial pathogens to the gastrointestinal mucosal surface (Voragen 1998). The most commonly used probiotics are lactobacilli and bifidobacteria. The reported beneficial effects of probiotics include alleviation of the symptoms of lactose intolerance, immune system enhancement, shorter duration of diarrhoea caused by rotavirus, decreased faecal mutagenicity, decrease in the levels of pathogenic bacteria, decreased faecal bacterial enzyme activity and prevention of the recurrence of superficial bladder cancer (Salminen et al. 1998). The choice of strain of micro-organism is important to avoid removal of micronutrients from the food, to avoid production of adverse components such as vasoactive amines and to avoid opportunistic lactic acid bacterial pathogens. Probiotic foods must contain living micro-organisms in appreciable numbers at the end of the product's shelflife. In Australia, fermented milk products, including yoghurt, must contain a minimum viable count of 106 organisms per gram at the end of the product's shelf life. Further research is required to confirm both the survival of

probiotics in foods and their efficacy in humans. Labelling that consumers might find useful in the future could include the declaration of the strain of pro biotic and the approximate numbers of viable cells present at the end of the shelf life.

Foods containing phytochemicals

Epidemiological studies have shown a correlation between people who consumed diets high in fruits and vegetables and a reduced risk of cancer (up to half compared to those consuming lower quantities). Examples of phytochemicals ('phyto' meaning plant) found in fruits and vegetables that may be biologically active in humans include flavonoids (anthocyanins, flavones, isoflavones, flavonols, flavanones), carotenoids (alpha, beta, lycopene, xanthophylls), allium sulfides, indoles and thiocyanates, monoterpenes and polyphenols (including tannins), spree antioxidants, phytosterols, fibres and brans. The beneficial effects of some phytochemicals are explained below.

Phytosterols

Phytosterols include the plant sterols, beta-sitosterol, campesterol and stigmasterol, and the related saturated phytostanols. Both plant sterols and plant stanols have been shown in clinical trials to be effective in lowering plasma total and LDL cholesterol by inhibiting the absorption of cholesterol from the small intestine. However, in order to achieve this cholesterol-lowering effect, approximately 1 g of phytosterols needs to be consumed per day. Normal intakes have been estimated to be 200-400 mg/ day in Western diets. In June 2001, ANZFA approved the use of plant sterol esters in edible oil spreads (margarines) as part of the Novel Foods standard in the Australia New Zealand Food Standards Code. Prior to this time, several products (in addition to enriched margarines) containing plant sterols were available in the Australian marketplace including enriched mayonnaise, salad dressing, yoghurt, breakfast bars and a milk product. These products were withdrawn from sale in June 2001 due to concerns by ANZFA that insufficient studies had been provided by the manufacturers to demonstrate their safety. ANZFA stated that 'there is sufficient data to demonstrate [the safety of plant sterol esters J at the level of intake which would be achieved from their use in edible oil spreads' (ANZFA 2001). Enriched margarines must be labelled

Chapter 8 New and emerging developments in food production 11 123

with an advisory statem~ent recommending that phytosterol-enriched products 'are not appropriate for infants, children and pregnant and lactating women and that people using cholesterol reducing medication should seek medical advice before using the spreads' (ANZFA 2001).

Flavonoids

Flavonoids are polyphenolic antioxidant compounds found in plant foods such as tea, onions, apples, soy, and coloured fruits and vegetables including berries, red cabbage, red grapes, eggplant and cherries (see Table 8.8). Epidemiological studies have shown increased intakes of certain flavonoids have been associated with a decreased risk of mortality from coronary heart disease. Other studies have shown that consumption of foods containing flavonoids, such as green tea, is associated with a decreased risk of cancer-for example, in Asia, a reduction in the risk of stomach cancer. Flavanols and flavones also inhibit the enzyme cyclo-oxygenase, resulting in lower platelet aggregation

Table 8.8 Flavonoids found in plant foods

Type of flavonoid Example of flavonoid

flavonols quercetin,

flavones

isoflavones

catechins (flavan-3-ols)

flavanones

anthocyan ins

kampferol, rutin, myricetin

apigenin

luteolin genistein daidzein epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate hesperidin, nobiletin, tangeritin, naringenin, neohesperidin cyanidin

delphinidin

pelargonidin petunidin peonidin malvidin

Food source

onion, kale, French beans, broccoli, lettuce, apples, red wine, tea citrus, millet, celery, parsley olive leaves soy flaxseed (linseed)

green tea, black tea

citrus fruits, honey

apple, red cabbage, cherry aubergine (eggplant) strawberry red grape cherry red grape, red wine

leading to a reduction in the tendency for thrombosis. Cyclo-oxygenase 1s also involved m the production of inflanunatory compounds within the body called prostaglandins. Green and black tea beverages contain significant levels of kaempferol, quercetin and myricetin. Green tea is produced by drying the leaves of the plant Camellia sinensis and has its characteristic colour due to the presence of colourless catechins. Black tea has been fermented prior to drying the leaves, causing the catechins to be oxidised to theaflavins, which have a bright orange-red colour. The addition of milk to green or black tea does not affect the concentration of the flavonoid, quercetin or catechins in plasma. However, flavonoids reduce the bioavailability of non-haem iron when tea is consumed with a meal, so tea is best consumed between meals. Anthocyanins have long been known as the natural colouring agents in a wide variety of plant foods including berries, red cabbage, red grapes, eggplant and cherries.

Phytoestrogens

Phytoestrogens are a group of non-steroidal compounds found in soy beans and flaxseed (linseed) which have properties similar to the endogenous (produced within the body) oestrogen hormone, 17 beta-oestradiol. Sub-groups of phytoestrogens include isoflavones (the main type of phytoestrogens found in food), lignans and coumestans. The main isoflavones include genistein, daidzein, formonetin and biochanin A. Phytoestrogens may be protective against cardiovascular disease; consumption of soy products has been found to be associated with significant reductions m total cholesterol, LDL cholesterol and plasma triglycerides. Epidemiological studies show that Japanese women who consumed traditional diets were found to have a decreased risk of cancer compared to Finnish women who consumed lower intakes of soy based foods. Animal studies have shown that in rodents, the consumption of flaxseed (linseed) is associated with decreased tumour formation of the colon, lung and mammary gland. Further research is required to determine whether the beneficial effects of soy are due solely to the presence of phytoestrogens, or whether the soy protein is also beneficial. The consumption of phytoestrogens by infants consuming soy based infant formulas also needs further investigation.

1:1 Part 11 Contemporary food use and safety

Lycopene

Lycopene is a carotenoid compound that does not have pre-vitamin A activity. It is the major carotenoid found in tomatoes (contributing to the red colour) and is also found in watermelon. A prospective study of more than 4 7 000 men found that those who consumed tomato products ten or more times per week had less than onehalf the risk of developing advanced prostate cancer (Giovanucci et al. 1995). Other studies have shown that increased intakes of tomato products are associated with a decreased risk of breast, digestive tract, cervical, bladder and skin cancers.

Glucosinolates

Brassica vegetables including broccoli, cabbage, kale, mustard, brussels sprouts and cauliflower contain glucosinolate compounds. If the dietary iodine intake is marginal or deficient, glucosinolates can exacerbate iodine deficiency through a glucosinolate metabolite, thiocyanate. However, if iodine intakes are adequate, then studies have shown that increased consumption of brassica vegetables is associated with a decreased risk of cancers from various sites. Research suggests that metabolites of glucosinolates, indoles (including indole-3-carbinol), appear to enhance the production of detoxifYing enzymes within the body. These enzymes block exposure of the target tissues to DNA damage and may assist by removing damaged cells of the colon by inducing apoptosis (programmed cell death). Interestingly, apart from the protective anticarcinogenic effects of consuming brassica vegetables, studies have shown a protective effect of consuming broccoli alone. The beneficial effect of broccoli is probably due to the compound sulforaphane. Sulforaphane is a major inducer of detoxifYing enzymes and inhibits enzymes within the body which activate some chemical carcinogens including N-nitrosamines. Three-day-old broccoli sprouts contain significantly higher levels of glucoraphanin (the glucosinolate of sulforaphane) than older plants.

Resveratrol

Grapes, especially red grapes, and red wine contain a polyphenolic antioxidant called resveratrol which has been shown to prevent oxidation of LDL cholesterol. Red wine contains twenty to fifty times more phenolic

compounds than white wine, due to the incorporation of the grape skins into the fermenting grape juice during red wine production. It has been suggested that resveratrol may be the agent involved in the so-called 'French paradox': France has relatively low rates of cardiovascular disease despite the French consuming diets high in dairy fat, and the French tend to have a moderate consumption of red wine. The protective effects of resveratrol include the inhibition of cellular events associated with tumour formation, promotion and progression and possibly inducing apoptosis. In addition, resveratrol has been shown to have some oestrogenic properties. However, alcoholic beverages of all types have been linked to the increased risk of several types of cancer, including breast cancer, and agerelated eye degeneration.

Garlic sulfides

Intact garlic contains the odourless sulfur-containing substance alliin. When garlic cloves are crushed, an enzyme, allinase, present separately in garlic tissue, catalyses alliin to the compound allicin. Allicin is responsible for the characteristic odour of fresh garlic. Allicin then decomposes to form many sulfur-containing compounds which have been found to inhibit carcinogenesis in animal studies. A large study conducted in China found that increased intake of garlic and onions (both Allium species) was associated with a decreased risk of stomach cancer. Another study of more than 40 000 postmenopausal women found garlic consumption reduced colon cancer risk by 50% (Stemetz et al. 1994). In vitro studies have suggested that allicin inhibits cholesterol synthesis within the body by inhibiting the liver enzyme, HMGCoA reductase.

Biotechnology

Biotechnology involves the use of micro-organisms, cell cultures or enzymes to produce foods, plants or animals or to develop micro-organisms for specific uses. Many food additives and processing aids are the product of biotechnology (see Table 8.9). Fermented foods are the

traditional products of biotechnology; examples include yoghurt, bread, wine, beer and cheese. Techniques used in modern biotechnology include recombinant DNA

Chapter 8 New and emerging developments in food production 11 125

(also known as 'gene technology'; see Table 8.10) and ~enetic engineering to selectively improve plants, :mimals and micro-organisms which then provide more desirable, predictable, precise and controllable foods than conventional cross-breeding techniques. Genes are segments of DNA that encode for particular proteins that can be synthesised within a cell. Genetically modified organisms (GMOs) are 'plants, animals and micro-organisms that have had DNA introduced into them by means other than by combination of an egg and a sperm' (Institute of Food Technologists 1999). Genetically modified foods (GMF) are derived from GMOs and defined by ANZFA as being foods which (as a result of the use of gene technology) contain novel DNA and/or novel protein or have altered characteristics. Genetically modified food does not include highly refined food, where processing has removed novel DNA and/ or novel protein, for example, highly refined sugar and oils. Biotechnological techniques involve placing copies of genes from the cells of a plant, animal or micro-organism and inserting them. into another cell (same species or different species) to synthesise (or increase the amount of) a protein or metabolite produced by an organism, or to block the production of a protein or metabolite by an organism.

Table 8.9 Ingredients and food additives produced by

biotechnology

Ingredient or food additive

Examples

---·- ·------- -----

preservatives

food acids

nutrients

propionic acid, nisin, pimaricin

lactic acid

vitamins C, D precursor, B-12, riboflavin, amino acids, omega-3 fatty acids

flavour enhancers monosodium glutamate, ribonucleotides

colours ~-carotene

enzymes

vegetable gums

a-amylase (for baking, brewing), glucose isomerase (for production of high fructose syrup), cellulase (fruit juice processing), ~-galactosidase (lactose hydrolysis of milk), chymosin (cheesemaking)

xanthan gum, gellan gum, guar gum, alginate

starter cultures yeasts, bacteria

flavours vanillin

vegetable oils vegetable oils with modified fatty acids e.g. monounsaturated sunflower oil

Source: Jensen 1993

The techniques for introducing DNA into an organism include using bacterial plasmids, which are circles of DNA snuller than the bacterial chromosome. Genetic modification (GM) uses special bacterial enzymes to 'cut and paste' genes from one organism into a bacterial plasmid at a particular point of the DNA sequence and the recombinant plasmid can then be inserted into another organism. Other methods of introducing genes include firing particles coated with the new DNA into a cell. Gene technology enables desirable genes, encoding for a wide range of traits, to be incorporated into a cell. Selective breeding techniques which have been used in the past may also transfer undesirable traits.

Regulation of gene technology in Australia and New Zealand

Various governmental departments and authorities are involved with the regulation of gene technology in

Table 8.10 Biotechnology terms

Term Definition --------------··-----·------

genetically modified a plant, animal or micro-organism organism that has had DNA introduced into it by

means other than by combination of an egg and a sperm or by natural bacterial conjugation

genetically modified food

novel DNA andjor novel protein

food produced using gene technology

gene technology

a food containing novel DNA and/or novel protein; or altered characteristics such as altered nutritional value, the presence of an allergenic factor. The intended use is different to the existing counterpart not produced using gene technology. The genetic modification may give rise to ethical, cultural and religious concerns (as a result of the use of gene technology)

DNA or a protein (as a result of the use of gene technology) which differs in chemical sequence or structure from DNA or protein present in the counterpart food

a food or food ingredient which has been derived or developed from an organism which has been modified by gene technology

recombinant DNA techniques that alter the heritable genetic material of living cells or organisms

Sources: Institute of Food Science and Technology 1999; ANZFA

2000b


Australia and New Zealand. While ANZFA's responsibilities include assessing the safety of consumption of genetically modified foods, the Office of the Gene Technology Regulator (Australia) is an independent statutory authority at the Australian Federal Government level, responsible for establishing legislation regulating all aspects of the development, production and use of genetically modified organisms. Table 8.11 shows the vanous government departments and authorities responsible for aspects of gene technology regulation in Australia and New Zealand.

Assessing the safety of GM foods

ANZFA has recently introduced a standard into the Australia New Zealand Food Standards Code regulating foods produced using gene technology, other than additives and processing aids, which are considered in other standards. In Australia and New Zealand there is a general prohibition on the sale of food produced using gene technology, unless pre-sale approval has been given by ANZFA after a thorough safety assessment on a case-by-case basis. Genetically modified foods approved for sale are specifically listed in the standard. ANZFA uses a decision-tree approach to identifY potential hazards with genetically modified foods, including the potential introduction of a novel allergenic protein, increased levels of naturally occurring toxicants in foods, altered concentration and/ or bioavailability of nutrients. Table 8.12 lists the criteria considered by ANZFA during the safety

evaluation of GM foods. Possible side effects of the use of genetically engineered organisms to produce food include the possibility of the presence or increase of allergenic proteins, and the presence of toxins or antinutrients in foods. Recently, a Brazil nut protein was introduced into soy beans in an attempt to improve their nutritional quality. However, some people are allergic to Brazil nuts (see Chapter 33) and the allergenic proteins were found in the GM soy beans; because of this the product was not commercialised.

Note that no food can ever be guaranteed to be absolutely safe for all persons in a population. The purpose of the safety evaluation is to ensure the level of safety associated with GM foods is at least that of nonGM foods.

GM foods approved for sale in Australia and New Zealand to date are shown in Table 8.13 and include foods derived from glyphosate-tolerant soy bean and oil derived from insect-protected cotton. Glyphosate is the active herbicide ingredient in the product Roundup. Glyphosate kills weeds by blocking the function of a plant enzyme EPSPS (5-enolpyruvylshikimate-3-phosphate synthase), normally required by plants to synthesise amino acids. Humans and other animals do not require the enzyme, because food contains the amino acids. The Monsanto corporation inserted a gene tolerant to glyphosate from the bacterium Agrobacterium (naturally occurring in soil) into soy bean plants. Glyphosate soy (genetically modified soy) produces two EPSPS enzymes, one is the soy bean version and the other is the bacterial version. During growth of the

Table 8.11 Government agencies involved with genetically modified foods in Australia and New Zealand

Activity Australian government agency New Zealand government agency

food safety Australia New Zealand Food Authority Australia New Zealand Food Authority

environmental issues including the release of genetically modified organisms

Office of the Gene Technology Regulator; Environmental Risk Management Genetic Manipulation Advisory Committee; Authority; Ministry for the Environment Environment Australia

imports and exports Australian Quarantine Inspection Service; Australia New Zealand Food Authority; Office of the Gene Technology Regulator; Genetic Manipulation Advisory Committee; Environment Australia

insecticide or herbicide issues including National Registration Authority for the registration of insect protected crops Agricultural and Veterinary Chemicals; and setting of residue limits in foods Therapeutic Goods Administration;

Environment Australia; Australia New Zealand Food Authority

Source: ANZFA 2000b

Ministry of Agriculture and Forestry; Ministry of Health

Ministry of Agriculture and Forestry; Ministry of Health


Table 8.12 Criteria used by ANZFA to determine the

safety of a GM food

• that all genetic material has been examined in detail

• that the genetic material is stable and is passed on in a predictable way from generation to generation

• that the new proteins have been examined in detail

• that the new proteins are unlikely to be toxic or allergenic

• that the new proteins do not cause any detectable toxicity in animal studies

• to ensure that the potential transfer of new genetic material to cells in the human digestive tract will not have a significant impact on human health

• to ensure that toxins, allergens and anti-nutrients in the GM food are not significantly increased compared to the levels naturally occurring in non-GM food

• to ensure the composition of the food is not significantly altered compared to the non-GM food

Source: ANZFA 2000b

plant, when glyphosate is used to kill weeds, the soy bean EPSPS enzyme is blocked but the bacterial version continues to synthesise amino acids, therefore the soy bean plant can survive.

Applications

Applications of biotechnology and animal nutrition include the breeding of leaner animals for food, resulting in lower fat cuts of meats (beef and pork), thereby offering consumers foods which enable them to select a diet which meets the Dietary Guidelines (see

Table 8.13 Genetically modified foods available for sale in

Australia and New Zealand

Food Trait Potential application

soy bean herbicide tolerance; soy foods and products high oleic acid soy containing soy beans including fat

modified foods

canola herbicide tolerance canola oil and foods containing canola oil

corn insect protection; corn foods and herbicide tolerance products

potato insect protection; virus potatoes and products protection

sugar beet herbicide tolerance sugar

cotton insect protection; cottonseed oil herbicide tolerance

Source: ANZFA 2000b

Table 8.14). Genetic engineering has the potential to select crops which are resistant to disease and attack by viruses, insects and environmental stresses. An important application of future genetic engineering of crops will be to improve the protein quality of cereal grains by increasing the quantity of limiting amino acids of certain grains; for example, increasing the concentration of methionine and cysteine in soy beans and lysine and tryptophan in maize. Since cereals are one of the world's most important sources of protein, genetic manipulation of particular crops will provide a more complete protein source for human diets. Other applications include the development of functional foods with increased content of biologically active substances, for example antioxidants and decreasing the levels of naturally occurring toxicants, such as lectins, in foods. Future applications for the development of genetically modified lactobacilli might include vitamin synthesis, biopreservatives, cholesterol reduction, anticarcinogenic activity, colonisation factors, competitive exclusion and enzyme production (Knorr et al. 1 998).

Other non-food applications of biotechnology include the production of human insulin for people with diabetes and tests based on monoclonal antibodies to detect substances in food such as aflatoxin and gluten.

Enzyme modification

Many endogenous enzymes 111 foods are involved in degradation processes such as the development of softening, oxidative rancidity and undesirable flavours and colours. Enzymes can be deactivated by heating the food during the process of blanching (see Chapter 5). Many enzymes, however, have beneficial functions in the processing of foods. Chymosin, the enzyme in rennet, for example, is used to coagulate the curd in cheese-making and glucose isomerase is used to hydrolyse starch to form high-fructose corn syrups.

A tomato recently approved in the USA, 'Flavr Savr' (FLAVR-SAVR is the registered trademark of Calgene), has been genetically engineered, using anti-sense RNA technology, to produce only 1% of the normal level of the enzyme polygalacturonase (PG). (Anti-sense genetic engineering involves producing the 'reverse' form of a gene, thereby inactivating expression of the gene.) This enzyme normally occurs in ripening tomatoes and catalyses pectin breakdown (hydrolyses a-1 ,4 linkages in polygalacturonic acid component of


Table 8.14 Use of biotechnology to improve the nutritional quality of foodstuffs

Application

increase the protein quality (concentration of limiting amino acids) of crops

increase the starch content of crops

improved nutritional value of crops

crops for use in adverse climates

herbicide resistant crops

decrease the fat content of animals for food

increase the efficiency of production of animal foods

alter the fatty acid composition of oil seeds

alter the amino acid content of foods

anti-sense RNA technology to inactivate specific enzymes in foods

plant tissue culture

fermentation

use of genetically engineered micro-organisms

alterations to the structure of enzymes used in food processing

cell walls) and subsequent softening of the fruit. As a result of the reduction in enzyme levels, tomatoes ripen on the vine without softening, thereby allowing flavour development prior to harvesting). Other advantages of the delayed softening of the tomato include reduced requirement for water and agricultural chemical use by farms, increased yield, reduced cost and an improved range of products utilising tomatoes. Another application of anti-sense RNA technology is to block the expression of a gene involved in caffeine production within the coffee bean (Gibson and Roberfroid 1995). This technology is expected to be used in the future to inactivate enzymes involved in the

Example

increase the concentration of sulfur-containing amino acids (methionine and cysteine) in soy beans; increase the concentration of lysine in cereal grains

reduces the uptake of oil into the potato during frying

rice enriched in vitamin A to prevent blindness in South-east Asia

crops resistant to drought, heat and salinity

soy beans resistant to glyphosate, cottonseed resistant to insects, potentially use less pesticides and herbicides

selective breeding techniques; use of porcine somatotropin (pST)

use of recombinant bovine somatotropin (bST)

increase the concentration of unsaturated fatty acids; increase the concentration of medium-chain triglycerides for special diets; increase the concentration of stearic acid as a functional replacement for hydrogenated fats

remove phenylalanine from wheat for people with phenylketonuria

delayed softening of tomato to improve flavour prior to harvest; reduction in natural toxicant production such as solanine in potatoes

synthesis of food additives (for example pigments, flavours, essential oils, enzymes, antioxidants, phytochemicals)

synthesis of food additives (for example amino acids, vitamins, food acids, flavours, flavour enhancers, pigments, antioxidants, preservatives); increase the vitamin content of food from raw state (for example niacin in tempeh)

synthesis of enzymes such as chymosin (for cheese-making) and glucose isomerase (for production of high-fructose corn syrups)

to immobilise enzymes used for continuous processing (for example rennet in cheese-making); to optimise functionality at conditions of pH and temperature used in food processing; to increase the activity of rennet

production of phytates and oxalates in cereals and vegetables in order to improve the bioavailability of minerals and to inactivate enzymes involved in natural toxicant production and oxidative rancidity.

Labelling of genetically modified foods

With the introduction of a standard (in the Australia New Zealand Food Standards Code) to regulate the sale of genetically modified foods, ANZFA has also introduced labelling provisions to enable consumers to make informed choices about the foods they eat. Foods are required to be labelled as 'genetically modified' if

Chapter 8 New and emerging developments in food production Ill 129

Table 8.15 labelling requirements for genetically modified foods (effective December 2001)

foods that must be labelled as ·genetically modified' on labels

ingredients containing novel DNA and/or novel protein

genetically modified ingredients to be identified in the ingredient listing, e.g. 'genetically modified soy flour'

foods containing novel DNA and/or novel protein

genetically modified foods to be labelled as part of the name of the food, e.g. 'genetically modified soy beans'

foods that do not require 'genetically modified' on labels

highly refined food where the refining for example, sugars and oils which have process removes novel genetic material been subjected to heating and other andjor novel protein processes

processing aids and food additives where novel genetic material and/or novel protein is not present

for example, the enzyme chymosin used to curdle milk in cheese-making is deactivated during later stages of cheese-making

flavours present at less than or equal to 0.1% in the final food

food prepared at the point of sale for example, restaurants, hotels, take-away foods

up to 1% of a genetically modified ingredient may be present in a food if its presence is unintended

for example, unintentional mixing of genetically modified and regular ingredient

foods labelled as 'genetically modified (GM) free'

must not contain any genetically modified ingredient, additive or processing aid

foods exempt from genetically modified labelling (above) cannot be labelled as 'GM free'

Source: ANZFA 2000

novel DNA and or novel protein is present in the final food or if the food has altered characteristics. At the time of this book's publication, the labelling regimen required in Australia and New Zealand is among the most stringent in the world. Table 8.15 shows the labelling requirements for genetically modified foods for sale in Australia and New Zealand.

Other issues with GM foods

Although genetically modified foods are subjected to a stringent safety evaluation process prior to sale, the use of genetically modified foods remains controversial because of the potential environmental risks of using this technology. In order to check whether the introduction of a gene into a cell's DNA has been successful, biotechnologists often introduce a second, marker gene. Until recently, these marker genes have often been antibiotic resistant genes. Concern has been raised over the potential for antibiotic resistant tracer genes to be transferred to other species such as microorganisms in the human digestive tract. Although the

risk of human gut microflora becoming resistant to antibiotics appears to be small, future biotechnological processes will most likely use alternative marker genes than antibiotic resistant genes if processing will not deactivate the gene (for example, yoghurt containing probiotics).

'Bt' is a commonly used abbreviation to denote the incorporation of the gene to produce crystal proteins from the Bacillus thuringiensis bacterium into other cells because the crystal proteins are toxic to insects including butterflies, moths, beetles and flies. While the crystal proteins are not toxic to humans, some groups have expressed concerns regarding the possibility that the toxic effects of Bt crystal proteins might reduce beneficial insect populations and that insects might become resistant to the action ofBt.ANZFA compares genetically modified foods with the natural counterpart, if one exists and has a history of safe use. Other concerns include the potential for cross-pollination of GM crops to non-GM crops, the possibility that herbicide resistance may transfer to weeds and the possibility of insects becoming resistant to pesticides.

130 B Part 11 Contemporary food use and safety

Organic foods

Despite popular usage, the term 'organic' can be misleading when referring to foods. AI! foods are orgamc since they are comprised of organic matter (molecules containing carbon).When applied to foods, however, this term commonly denotes methods of food production which have not employed synthetic chemicals such as pesticides and fertilisers. Alternative terms include 'biodynamic', 'biological' and 'ecological'. It is important to note that 'organic' foods are not necessarily free of pesticide residues and other contaminants; levels ofthese in foods will depend upon factors such as the quality of soil and exposure to environmental pollution. Organic farming relies on techniques of sustainable agriculture to achieve adequate nourishment of plants and biological pest control methods to control weeds, insects and other pests. The Organic Produce Advisory Cm=nttee (OPAC) of the Australian Quarantine Inspection Service (AQIS) developed a non-mandatory code of practice for the exportation of organic and biodynamic produce (OPAC 1998). It outlines minimum standards for exported food to be labelled as organic. While consumers may wish to choose foods which have used different farming techniques in their production, so-called 'organic foods' are not nutritionally superior to the regular counterpart farmed by conventional agricultural methods. AQIS undertakes the accreditation of orgamc and biodynamic industry organisations. Organic foods for export cannot be labelled as such if the food is derived from genetically modified organisms or has been subjected to ionising radiation. A limited study comparing the nutritional value of potato, broccoh, cauliflower and tomato grown by conventional or organic farming methods showed that for the nutrients analysed, the organically grown vegetables were not nutritionally superior to the conventionally grown produce. Similarly, the Institute of Food Technologists (US) concluded that there is no evidence of a nutritional or otherwise health benefit of organic foods over those that are farmed conventionally (Institute of Food Technologists 1990).

NEW DEVELOPMENTS IN FOOD PROCESSING TECHNIQUES

Minimal food processing

Minimal food processing or preservation techniques are those which cause little change to the 'freshness' attributes of a food while giving sufficient treatment to the food to extend shelf life for the consumer beyond the limited number of days the food in its raw state would normally have. Examples of minimal processing techniques include storage methods for fruits and vegetables (controlled atmosphere storage), nonthermal methods of food processing (high pressure treatment, irradiation, high electric field pulses), thermal processing methods (ohmic heating, microwaving, sous vide and high frequency heating) and new packagmg technologies (nwdified atmosphere packaging, active packaging, edible films).

Food irradiation

Ionising radiation such as X-rays, beta-rays and gamma-rays all have very short wavelengths and are harmful to living organisms either by the direct effect of damaging DNA or indirectly, by producing reactive compounds such as superoxide anions and hydroxyl radicals from oxygen and water in the organism or its environment. The most penetrating radiation is from gamma-rays produced by cobalt-60 or caesium-137.

Irradiation of food involves using ionising radiation to destroy various micro-organisms or to inhibit biochemical changes. Certain bacteria (Salmonella, Campylobacter, E. coli, Listeria, Vibrio) and food-borne parasites (for example, Trichinella, toxoplasma) are susceptible to ionising radiation. Viruses and bactenal toxins are particularly resistant to ionising radiation.

In Australia, as a result of public concern over safety issues food irradiation is currently not generally per~tted. However, ANZFA will consider applications to irradiate foods on a case-by-case basis. At the time of writing, there were no irradiated foods permitted to be sold in Australia and New Zealand. However, the Joint FAO/WHO CodexAlimentarius Commission accepted food irradiation as a safe and effective technology when used under good manufacturing practices (GMP). The World Health Organization and International Atomic Energy Authority has recmmnended that doses up to 10 kGy are acceptable without extensive toxicological


clearance. The process has been used in many countries at low dose levels to inhibit sprouting (of onions and potatoes), delay ripening (of fruit), destroy insect larvae and eggs (in grain) and kill protozoa and helminthic parasites (in pork, beef and fish). It is the only process that can eliminate Salmonella spp. from frozen meats and poultry products, as well as from bulk animal foods. (See Table 8.16.)

Other non-thermal processing techniques

High pressure treatment of food has been used in Japan to prolong the shelflife offruit products (Ohlsson 1994). Very high pressures applied to foods is expected to rupture the cell wall of micro-organisms and inactivate enzymes, coagulate proteins and swell starches. Depending on the pressure applied, reversible or irreversible protein denaturation may occur. Other applications of ultra high pressure treatment may include lowering the antigenic potential of whey protein hydrolysates (compared to heat treated whey protein). Electrical pulse treatment of food using field strengths of 1G-20 kV I cm causes rupture of cell membranes and therefore inactivation of micro-organisms, in particular yeasts. This technique is likely to be used for fruit products, may help to preserve the antioxidant content of fruit juices and may be used in the future in the manufacture of novel functional foods.

Table 8.16 Advantages and disadvantages of food

irradiation

Advantages

little or no heat involved

packaged and frozen foods may be irradiated

nutrient losses comparable to other food processes

reduced incidence of food-borne disease

facilitate wider trade

Disadvantages

public resistance due to fears of radioactivity (radionuclides) and occupational safety concerns

inadequate analytical methods to detect actual irradiated dose applied

potential for development of micro-organisms resistant to irradiation

oxidation of fat-soluble compounds and fatty acids, development of rancidity in fatty foods

reduce post-harvest food losses

no residues (unlike fumigation)

New thermal processing techniques

Thermal processing is a common and effective method of destroying spoilage and pathogenic bacteria. Traditional methods of thermal processing include cooking, baking, canning and pasteurisation. Recent methods of using heat to process foods include the use of microwave and ohmic heating. Microwaves cook food by agitating water and other small molecules to produce frictional heat. This occurs rapidly, starting mternally rather than from the outside. Continuous microwave processing can be used for pasteurisation, sterilisation, drying, blanching, thawing and tempering of frozen foods and baking. No specific, direct antibactericidal properties of microwaves have been shown-they kill micro-organisms by a thermal effect (Fellows 1988). Variable composition in food may lead to 'hot spots' where greater destruction may occur, and also 'cold' spots. If food reaches temperatures obtained by conventional cooking and is held there for a similar time, then equivalent control is given. Dried foods such as spices will have no significant reduction in microbial population after microwave treatment, due to a lack of polar molecules (mainly water) to agitate to produce heat. Ohmic heating involves passing an electric current through an electrically conducting food. The electrical energy is converted to thermal energy, to an

~nli~ted depth of penetration without forming a s1gmficant thermal gradient (that is, heat is distributed evenly). Unlike the traditional thermal process applied to canned foods (see Chapter 5), the rate of heat penetration to the slowest heating point with ohmic heating is dependent on the electrical conductivity of the food and less on the size of the particulates. Applications include processing of fruit, vegetables and soups. Heated products can be aseptically packaged to enable the product to be shelf stable.

Micronisation involves heating foods in the mid infra-red wavelength range (1.8-3.4 Jlm, for usually less than five minutes. Infra-red heating can be used to reduce microbial load, gelatinise starch in cereals and reduce the activity of anti-nutritional factors such as trypsin inhibitors in cereals.

Separation techniques-membrane processes and extraction

Ultrafiltration and reverse osmosis (see Table 8.17) are examples of membrane processes used to concentrate


Table 8.17 Application of ultra-filtration and reverse

osmosis

Ultra-filtration

for dilute solutions to concentrate milk in dairy product manufacture; to concentrate whey; to selectively remove lactose, salts, soluble minerals, water soluble vitamins, non-protein nitrogen compounds; to standardise milk

to concentrate sucrose and tomato paste

Reverse osmosis

for dilute solutions to concentrate milk, whey (from cheese manufacture) prior to dehydration or for use in ice-cream manufacture (by removal of water and ionised minerals)

to purify juices prior to evaporation, to concentrate enzymes and vegetable oils

to separate and concentrate to concentrate wheat starch, enzymes

pre-treatment for reverse osmosis membranes to prevent fouling

citric acid, egg white, milk, coffee, syrups, natural extracts, flavours

clarification of beer and wine

demineralisation and purification of water

solutions and selectively remove solutes by passing the solution across a semi-permeable membrane to yield two liquids with differing composition. Reverse osmosis uses high pressure to concentrate solutions with high osmotic pressure (low molecular weight solutes). Ultrafiltration uses a lower pressure to remove large molecules such as proteins and colloids with a lower osmotic pressure. In contrast to evaporation, membrane concentration does not require the application of heat. Membranes used in ultrafiltration contain large pore sizes and therefore there can be substantial loss of sugars, water soluble vitamins and amino acids from milk, for example.

Extraction

Supercritical fluid extraction is a technique used to extract components from foods without the deleterious effects on flavour or composition which can occur with processing at high temperature. This is a form of mild or minimal food processing. Supercritical fluids (substances above their critical temperature and pressure) have physical properties intermediate between gases and

liquids. Carbon dioxide is the most commonly used supercritical fluid (SCF); it is non-toxic, non-flammable, has a critical temperature of 31.1 °C and is therefore used for heat labile materials at low temperatures, and there is little or no residual carbon dioxide in the food. Applications include decaffeination of coffee, extraction of hops, extraction of oleo resins from herbs and spices, defatting of potato chips and peanuts, extracting cholesterol from egg yolk powder, extraction of evening primrose oil from the seed and the extraction of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oils.

NEWER FOOD PACKAGING

Packaging serves many purposes. It protects food from external contamination (micro-organisms, contaminants, pests), may enclose a desirable gaseous atmosphere (see 'Vacuum and modified atmosphere packaging' below) which affects the microbiological safety of the food, provides a barrier to gaseous transfer, conveys information to the consumer regarding the contents of the food (labelling), provides physical protection during transportation and storage and may have an impact on the nutritional quality of the product (for exam.ple, opaque materials reduce riboflavin losses from milk). Packaging may also contain special features such as tamper evident mechanisms and sensor indicators of correct storage conditions such as temperature.

Vacuum and modified atmosphere packaging

Vacuum packaging involves placing the product in a plastic or aluminium foil pouch and withdrawing most of the air (0.3-3% may remain) prior to sealing. Sous-vide is a processing technique where food is vacuum packed then heated (usually pasteurised) to extend shelf life while maintammg organoleptic qualities. Products are vacuum packed prior to pasteurisation, giving an improved shelf life under refrigerated conditions (less than 3°C). Modified atmosphere packaging (MAP) relies on altering the composition of gases in contact with the food within the package by replacing air with a single gas or mixture of gases, combined with low temperature storage (less than 3°C) (see Figure 8.2). Increasing the concentration of carbon dioxide (up to 10%) inhibits the growth of bacteria and fungi. Typically, concentrations of carbon

Chapter 8 New and emerging developments in food production 11 :L33

(a) Modified atmosphere packaging: low oxygen

tray

film

I

food with water activity > 0.92, pH > 4.5, e.g. vegetables

Note: Storage less than 3°C is critical in order to control growth of anaerobic pathogenic micro-organisms.

(b) Modified atmosphere packaging: red meats

(c) Active packaging

tray ...

tray ...

ethylene scavengers impregnated into film

Figure 8.2 Examples of recent packaging systems

film

! j

I

meat

film

! j ,

ethylene

+

fruits/vegetables

gas atmosphere: low oxygen to control growth of aerobic pathogenic micro-organisms

gas atmosphere: 80% oxygen, 20% carbon dioxide to retain 'red' colour of meats (oxymyoglobin)

release of ethylene during ripening


dioxide of20-1 00% are used in MAP Depending on the type of food being stored, oxygen concentrations may be nil or very low, excepting MAP of fresh red meats where oxygen is important in maintaining a 'fresh' red colour. Nitrogen is often used to displace oxygen. The aim of MAP is to exclude oxygen and retain the moisture content of the food and to inhibit the growth of aerobic micro-organisms. Facultative anaerobic bacteria such as Clostridia and Enterobacteriaceae (for example, E. coli, Salmonella) are less affected by MAP than aerobic micro-organisms. Under anaerobic conditions, control of anaerobic pathogens requires particular attention to the water activity and pH of the product and to storage temperature. The HACCP system (see Chapter 6) is important in ensuring attention to temperature control, for example, is maintained.

Packaging materials commonly used for MAP of fruits and vegetables are flexible plastic films, typically PVC, polyethylene, polypropylene and polystyrene. Films with varying permeability to oxygen, carbon dioxide and water vapour are used for different applications. The choice of a flexible packaging material will depend on the recommended storage temperature of the final product, the relative humidity within the package, the respiration rate of the produce and effect of light, if any, on the contents (for example, potatoes need to be packed in opaque films to prevent solanine development; see Chapter 7) .Vacuum packing and MAP reduce oxidative rancidity and are therefore useful for products prone to rancidity such as high fat foods.

Active packaging

In active packaging, materials are added to modify the composition of gases during storage (see Figure 8.2). Oxygen scavengers (adsorbers) present in the food package reduce the level of oxygen in the headspace (the space between the top of the food and the packaging material). Ionic iron (Fe2+) is often used where it is oxidised to Fe3+. Reducing the level of oxygen in the headspace reduces the growth of aerobic micro-organisms (see Chapter 6) and delays the development of oxidative rancidity. Another example of active packaging is the use of ethylene scavengers in films produced for packaging fruits and vegetables. As fruits and vegetables ripen, they release the ripeningstimulating hormone ethylene; by scavenging the ethylene, the ripening process is delayed, thereby increasing the shelf life. Other potential applications include incorporating ascorbic acid or vitamin E (vitamin antioxidants) into packaging films to retard the oxidation of food components.

Edible coatings

Edible coatings may be made from films of proteins, waxes or starches. The coatings protect the food from external oxygen, minimise loss of water vapour (moisture) and volatile components. Applications are likely for products which are dry, frozen and semi-moist.

SUMMARY • Foods can be modified to meet particular dietary requirements, for example gluten-free foods

for people with coeliac disease.

• Functional foods are foods where biologically active substances are either increased or decreased in order to offer the consumer the potential benefit of enhancing their health or reducing the risk of disease.

• Advances in research have increased the awareness of beneficial naturally occurring biologically active substances in natural functional foods such as fruits and vegetables.

• Modern biotechnology, including gene technology and genetic engineering, can result in selective improvements in plants, animals and micro-organisms which are used as foodstuffs.

• New food processing technologies include minimal food processing, food irradiation, thermal and non-thermal processing techniques, separation techniques, extraction and newer food packaging systems.

Contemporary food use: Food supply and food intake Jngrid H.E. Rutishauser

OBJECTIVES

• To provide an understanding of the basis on which national food supply statistics are compiled.

• To describe the limitations of national food supply data.

• To describe trends in the Australian food supply.

• To provide an understanding of the principal methods used for collecting information on food intake.

• To discuss the advantages and limitations of different methods of collecting information on food intake.

• To describe the major influences on food intake patterns.

152

DERIVATION OF FOOD SUPPLY DATA

In Australia the major source of information on the food supply is the Apparent Consumption of Foodstuffs series produced annually, since 1936-37, by the Australian Bureau of Statistics (ABS). Similar information, referred to as food balance sheets, is collated for most countries in the world by the Food and Agricultural Organization of the United Nations (FAO) and is available on line at <www.fao.org>. A food balance sheet is basically the amount of food that is available for human consumption, in a country in a given year, after taking into account the production, changes in stocks, imports and exports of foods, and allowing for agricultural and industrial uses of foodstuffs. It is important to remember that this is not the same as the amount of food that is actually eaten by the population. Figure 10.1 shows the basic steps in the derivation of a food balance sheet.

Usually national food supply data are expressed in terms of kilograms per head per year or grams per head of the population per day. These figures represent a national average and should not be equated with the annual or daily consumption or intake of individuals. They cannot replace data on food intake since the information provided by food balance sheets or

Chapter 10 Contemporary food use: Food supply and food intake I[

'apparent consumption data' cannot be disaggregated to describe food patterns for population sub-groups that differ in age, gender or geographical location. Food balance sheets primarily provide a practical way of looking at trends in the food supply, over time, both within and between countries. Three-year averages, rather than annual data, are usually presented. While every effort is made by FAO to standardise the derivation of the data, valid comparisons between countries inevitably also depend on the reliability and comparability of the original data provided to FAO.

COMPARISON OF FOOD SUPPLY DATA BETWEEN COUNTRIES

Table 10.1 shows FAO food balance sheet data for selected commodities for the years 1992-94 for Australia, for some countries in South-east Asia and for the countries of origin of the principal groups of European migrants to Australia. It is evident from the table that there are major differences between countries in the composition of the food supply. In general the food supply of neighbour countries, with the exception of New Zealand, is much higher in cereal foods and lower in animal products than the food supply of Australia and the European countries of major groups of migrants to Australia. In contrast the per capita supply of fruit and vegetables is highest in Southern Europe (Greece and Italy), intermediate in Australia, New Zealand and Japan and lowest in the South-east Asia region. In part the low fruit and vegetable supply in the South-east Asia region is likely to reflect the difficulty of accounting for home production in food balance data. This is another illustration of the need for actual data on food intake in order to be able to assess

1 Figure 10.1 Steps In tbe derivation of a food balance sheet (WHO 1991}

accurately differences in the nutrient content of the food eaten by different population groups.

APPARENT CONSUMPTION OF FOODSTUFFS AND NUTRIENTS IN AUSTRALIA

As already indicated, these data provide the major source of information of changing trends in the Australian food

Table 10.1 Comparison of FAO food balance sheet data for Australia and selected countries, 1992-94

Available food supply gjhead per day Country Cereals Roots Vegetables Fruit Meat Eggs Fish Milk

Australia 238 161 206 288 296 21 49 747 Fiji 401 242 73 52 125 9 94 164 Greece 403 218 615 579 192 31 64 634 Indonesia 561 181 65 90 22 7 43 16 Italy 422 120 446 399 236 33 59 678 Japan 400 99 292 161 109 55 183 187 Malaysia 403 76 79 142 126 39 78 71 New Zealand 263 164 220 292 317 34 45 598 United Kingdom 255 292 250 220 185 28 51 598

Source: FAO 1996


supply over the last five decades. The method used to calculate the data is similar to that used for the FAO food balance sheets with the exception that the reporting is not limited only to primary produce. For example, there is information about the amount of sugar used in manufactured foods and the amount of milk used in producing cheese. Historically the Australian Bureau of Statistics' publication Apparent Consumption of

Foodstuffs and Nutrients, Australia (Cat. No. 4306.0) has developed as a byproduct of commodity data collected by government agencies for economic and other purposes. This means that there is some variation in the coverage and reliability of the data for different commodity groups. The method generally used to estimate consumption is shown in the box.

Apparent consumption =

(commercial production + estimated home production + imports + opening stocks) m1nus (exports + usage for processed food + non-food usage + wastage + closing stocks)

This equation is not used for those commodities for which some components of the equation are not available, or where a more appropriate way of deriving consumption is available. For example, the equation is not used for milk, some milk products, cheese, rice, bread, eggs, beer, wine, spirits and dried fruit. Another exception, which is relevant to current dietary recommendations, is the consumption estimate for edible oils. This quantity has always been estimated rather than derived from annual commodity statistics and revised only twice since Apparent Consumption cif Foodstuffs and Nutrients, Australia was first produced. Limitations such as these have been often overlooked when the data were used to describe the Australian diet or to set nutrient related national goals and targets in the absence of national data on actual food intake.

TRENDS IN THE AUSTRALIAN FOOD SUPPLY

While the Apparent Consumption of Foodstuffs series of publications provides essentially continuous data on the food supply since 1936-37 there have been some changes, both in the commodity and the nutrient database, over this period. These need to be taken into

account when assessing the real impact of apparent changes over time. Figure 10.2 shows the trends in the availability of major food commodities, from 1938-39 to 1998-99 based on averages for the last three years of each ten-year period (ABS 2000a).

Meat and meat products

While there has been a continuing trend for per capita consumption of meat and meat products to fall throughout the period, to some extent this decrease has been replaced by poultry and seafood consumption that has increased. Nevertheless, the combined annual consumption of meat and meat products, poultry and seafood in the period ending 1998-99 was 7 kg (~5%) less than in 1938-39 (122 v 129 kg per head).The main changes have been the substitution of beef and mutton by poultry and pork. Lamb has also largely replaced mutton and the combined consumption of mutton and lamb is only about half that of 1938-39. Seafood consumption, while double that of 1938-39, was still relatively low at about 11 kg per head per year in the period ending 1998-99.

Dairy products

In contrast to meat and meat products, per head consumption of dairy products, expressed in terms of milk solids, has gradually increased since 1938-39. Consumption of fluid milk in the period ending 1998-99 was almost the same as in 1938-39 but had been 30% to 40% higher between 1948-49 and 1968-69. The increase in dairy product consumption since 1938-39 is due, almost entirely, to an increase in cheese consumption. Apparent consumption data currently provide no information on the proportion of the dairy product supply that is available as reduced fat products.

Grain products

Overall consumption of grain products, expressed in terms of flour, breakfast foods and table rice, has increased since 1938-39 but is less than in 1948-49 when it was close to 100 kg per head. The lowest level of consumption was recorded in 1978-79 at 80 kg. Since then consumption of grain products has risen only slightly to 84 kg in 1998-99, mainly due to an increase in table rice. Consumption of grain products

kg 125

115

105

95

85

75

kg 130

120

110

100

90

80

70

60

Chapter 10 Contemporary food use: Food supply and food intake • 155

Apparent per capita consumption of meat and meat products

19381948195819681978 1988 1998 -39 -49 -59 --69 -79 --89 -99

Average 3 years ended

Apparent per capita consumption of fruit and fruit products

1938 1948 1958 1968 1978 1988 1998 -39 -49 -59 --69 -79 --89 -99


kg 27

25

23

21

19

17

kg 165

155

145

135

125

Apparent per capita consumption of dairy products as milk solids

1938194819581968197819881998 -39 -49 -59 --69 -79 --89 -99


Apparent per capita consumption of vegetables

\ /--· /

115

1938194819581968197819881998 -39 -49 -59 --69 -79 --89 -99


kg 105

Apparent per capita consumption of grain products

95

85

75

1938 1948 1958 1968 1978 1988 1998 -39 -49 -59 --69 -79 --89 -99


Figure 10.2 Trends in the availability of major food commodities in Australia since 1938-39 (ABS 2000a)


in the form of bread, however, has increased by 20% since 1988-89.

Fruit and fruit products

Consumption of fruit and fruit products has increased steadily since 1938-39 and was 127 kg per head per year in the period ending 1998-99 as compared with 70 kg to 80 kg per year in the period between 1938-39 and 1958-59. Most of this is due to an increase in citrus fruit consumption from around 15 kg in 1938-39 to 49 kg in 1998-99. Consumption of other fresh fruit, however, has also increased by about 12 kg per head per year from 43 kg in 1938-39 to 55 kg in 1998-99. The main effect of these increases has been to double the apparent per capita consumption of vitamin C from just over 50 mg per day in 1938-39 to around 110 mg per day in 1993-94.

Vegetables

Information on vegetables, other than potatoes and tomatoes, has been available since 1948-49. At that time total vegetable consumption was around 130 kg per head per year. Vegetable consumption did not increase to any extent until 1988-89 when it reached 148 kg. Recent years have seen a further increase to 162 kg in 1998-99. The increase in vegetable consumption since 1988-89 is due to an increase in consumption of potatoes, root vegetables and tomatoes, while consumption oflea£Y and green vegetables has shown a small decrease. Potatoes have accounted for between 40% and 45% of total vegetable consumption throughout the whole period.

Sugars

Total consumption of sugars has changed only slightly since 1938-39. The highest level of consumption was recorded in 1948-49 when it was around 57 kg per head per year. Consumption in 1938-39 was 51 kg and 4 5 kg in the period ending 1998-99. The main change has been that the proportion of sugar consumed in manufactured foods and syrups has risen while the amount consumed as refined sugar has fallen. While much has been made of this change, it largely reflects the fact that many baked goods and desserts that used to be prepared at home are now available from bakeries,

patisseries and supermarkets.

Oils and fats

As already indicated the apparent consumption of vegetable oils and edible fats other than butter and margarine is an estimate. This amount is currently estimated at 10 kg per head per year; prior to 1975-76 it was estimated at 2 kg. Figure 10.3 illustrates the changes in butter and margarine consumption since 1938-39. Butter consumption in 1938-1939 was 15 kg per head per year and ~4 kg in 1998-99 including dairy blends. In contrast margarine consumption rose from about 2 kg in 1938-39 to 8 kg in 1978-79 but has since declined to <7 kg in the period ending 1998-99. While the increase in margarine consumption is less than the fall in butter consumption the difference is more than made up by the estimated consumption of 10 kg of edible oils per head per year. The estimated consumption of fats and oils in 1998-99 was ~3 kg less than 1978-79 but still higher than in 1938-39.

kg

15

10

5

0

Apparent per capita consumption of butter and margarine

total margarine

table ----margarine

1938 -39

1948 -49

1958 -59

1968 -69

margarine

1978 -79

1988 -89


1998 -99

Figure 10.3 Apparent consumption data for table spreads

and sugars in Australia 1938-93 (ABS, 1995)

Chapter 10 Contemporary food use: Food supply and food intake • 15 7

Beverages

Consumption of both non-alcoholic and alcoholic beverages has shown some major changes since 1938-39. Coffee consumption has steadily increased from 0.3 kg to ~2 kg per head per year while tea consumption has declined from 3.1 kg to less than 1 kg per head per year in the period ending 1998-99. The consumption of aerated and carbonated beverages has more than doubled from 47 L in 1968-69 to 112 L in 1998-99. Beer consumption has fallen from a high of 133 L in 1978-79 to 94 L in 1998-99 but is still almost twice the 1938-39 consumption of 53 L per head per year. Since 1991-92 low alcohol beer accounted for 20-25% of total beer consumption. Consumption of wine increased steadily from 3 L in 1938-39 to around 20 L per head per year since 1988-89.

NUTRIENTS AVAILABLE FOR CONSUMPTION

An estimate of the nutrients available for consumption from the Australian food supply data can be derived using food composition data. Until 1967-68 the food composition tables used were those compiled by Osmond and Wilson (1954) and from 1967-68 until 1987-88 those of Thomas and Corden (1977). Since 1987-88 the data used have been those published in volumes 1 to 7 of the Composition of Foods Australia

(Lewis et al. 1995). These periodic but substantial changes in the nutrient database, while providing more

up-to-date nutrient data, have also resulted in some discontinuities in the nutrient estimates and this means that it is no longer possible to compare directly current nutrient estimates with those published prior to the introduction of these revisions. Since 1987-88 updates and additions to the nutrient database have been incorporated as they become available and for this reason major discontinuities in the nutrient estimates are now less likely to occur. Table 10.2 taken from Apparent Consumption shows the estimated nutrients available for consumption from 1938-39 to 1993-94, the final year in which nutrient data were published by the ABS in Apparent Consumption. Since 1994-95 the responsibility for compilation of nutrient estimates from Apparent Consumption has been with the Australian Institute of Health and Welfare. In Table 10.2 adjustments have been made for losses of vitamin C and thiamin in cooking and for the extra niacin obtained from the metabolism of protein. While the changes in the nutrient composition database described above affect, to some extent, the comparability of the data at specific points in time they are unlikely to invalidate longer term trends. Table 10.2 suggests that the overall energy and protein values of the total food supply have changed relatively little in the period between 1938-39 and 1993-94. The real long-term trends in fat and carbohydrate consumption are more difficult to gauge. All that can be said is that the estimate of fat available for consumption in 1988-89 was lower than at any time previously and has decreased further since then. In contrast the amount of carbohydrate, which was also lower in 1988-89 than at any time in the past, appears

Table 10.2 Estimated nutrients available for consumption in Australia 1938-39 to 1993-94

Nutrient* 1938-39 1948-49 1958-59 1968-69 1978-79 1988-89 1993-94 Amount available per head per day

protein: animal (g) 59 57 60 64 69 63 64 vegetable (g) 31 35 32 36 32 37 39

fat, all sources (g) 134 122 132 123 153 119 117 carbohydrate (g) 377 425 417 407 396 375 383 calcium (mg) 640 785 815 970 875 890 878 iron (mg) 15.4 15.1 14.0 14.7 15.7 12.4 12.9 retinol (flg-equiv) 1470 1390 1370 1350 1600 2570 2389 vitamin C (mg) 53 59 54 60 73 101 109 thiamin (mg) 1.2 1.3 1.1 1.4 1.5 1.4 1.5 riboflavin (mg) 1.7 1.9 1.8 2.7 2.7 2.4 2.4 niacin (mg-equiv) 33 32 33 36 41 41 41 energy (kJ) 13050 13580 13800 13840 14640 12910 12945

*Three-year average for the period ending

Source: ABS 1997b


to have increased in recent years. With the exception of iron, the availability of all other nutrients has increased over time. The increase in the vitamin C supply, as already indicated, is primarily a consequence of the increase in citrus fruit supply while the increases in calcium and riboflavin are primarily due to the increase in cheese consumption.

OTHER SOURCES OF INFORMATION ON THE FOOD SUPPLY

Retail food sales

Information about the Australian food supply can also be obtained fron1 data on the amount of food traded at retail and/ or wholesale level. Such data are derived mainly frmn food industry organisations and firms engaged in food production and marketing. Commercial databases such as those produced by the AC Nielsen Company, and the electronic stock control records from individual supermarkets, from which the databases are compiled, have the potential to be used for monitoring trends in the food supply, at a product specific level, not only at a national but also at regional and local level. Their principal disadvantage, at present, lies in the high costs associated with processing or otherwise accessing, on a regular basis, the very large amounts of data that are involved. Supermarkets have increased enormously in importance as retail food outlets since the first self-service supermarkets came into operation in Australia in the 1950s. The four major chains now hold more than 95% of the packaged goods market in Australia and their share of the fresh produce market (fruit, vegetables, meat and seafood) continues to increase. Because of their overriding share of the grocery market and because a very high proportion of supermarket checkouts in Australia use electronic scanners, supermarket scanning data have the potential to provide an ongoing and up-to-date source of information on changing patterns of food availability and expenditure. Possible applications for checkout data are to use them to track the constantly changing range of products in the food supply, to compare differences between communities with different socioeconmnic characteristics and to assess community level changes in food expenditure patterns in response to nutrition education and intervention programs. A study conductedjointly with a major supermarket chain compiled

data on food sales from twelve supermarkets in Melbourne over a twelve-month period beginning in March 1993. During this period the number of different food products sold during a trading week increased from an average of 5800 to 6100. These figures give some indication both of the diversity of the current Australian food supply and the rate at which it is changing. They also serve to illustrate the problems likely to be encountered in maintaining up-to-date information on the Australian food supply, not only in terms of foods but also in terms of the nutrients that they provide.

Apparent Consumption, Household Expenditure and Retail Sales Data all provide information on the food supply and not food intake.

Household food expenditure

Another source of information on the food supply in Australia is the Household Expenditure Survey (HES) conducted by the ABS every five years. The HES collects information on household income and all expenditure over a period of two weeks. Unfortunately, from a nutritionist's point of view, no data are collected on the amounts of food purchased. The primary reason for this mnission is that the collection of the additional data would markedly increase respondent burden. The inclusion of information on food quantities, however, would increase the value of the data enormously and hopefully, as the proportion of food purchases that is electronically recorded increases, the additional burden on respondents will decrease to the extent where the collection of this additional information becomes feasible. Even though HES data currently cannot be used to obtain quantitative information on household food consumption patterns, they do allow comparisons of expenditure patterns between households from different areas, households of different composition and households with different levels of income. Comparisons of the latter have shown that while the total amount of money spent on food rises with income, the proportion of total income that is spent on food tends to decline. In 1998-99 the average weekly household expenditure on food and non-alcoholic beverages of Australian households was $6 7.15 for the lowest quintile of income and $194.91 for the highest quintile. As a proportion of total expenditure, the


proportion spent on food and non-alcoholic beverages was 20% in the lowest quintile of income and 17% in the highest quintile (ABS 2000b).While the proportion of expenditure on food eaten away from home tends to rise markedly with income, the proportion spent on other foods tends to remain much the same or to decline. It should be noted, however, that differences in food expenditure with household income are not solely a function of income but also reflect other household characteristics, such as age and household size. Contrary to common belief, the proportion of expenditure on fast foods and meals eaten away from home has not risen in recent years. These foods accounted for 27% of the total expenditure on food and non-alcoholic beverages in 1993-94 and a similar proportion (26%) in 1998-99.

USES OF FOOD INTAKE DATA

While food supply and household food expenditure data can be used to describe trends in the amounts and types of food available for consumption by the population and by households, these data cannot tell us about the amounts, combinations and types of food actually consumed by individuals. This kind of information is needed by administrative, regulatory and health authorities for a variety of purposes including:

1 development and, in turn, evaluation of the impact of nutrition policies and programs;

2 assessment of dietary and nutrient adequacy by comparison with Dietary Guidelines for Australians and Recommended Dietary Intakes (RDI);

3 risk assessment by regulatory agencies such as the Australian and New Zealand Food Authority (ANZFA) in respect of additives, contaminants and pesticide residues in foods;

4 epidemiological studies of the relationship between food intake and the development of nutrition related conditions such as obesity and cardiovascular disease.

METHODS OF MEASURING FOOD INTAKE

Accurate measurement of food intake in individuals has been described as one of the most difficult tasks undertaken by nutritionists. The main reasons for this are that:

1 the food supply, particularly in countries such as Australia, is extremely varied;

2 individuals eat widely differing amounts and combinations of food from day to day;

3 the task of recording in detail all the foods eaten, even over a short period of time, is time-consuming and demands a high level of cooperation from the respondent.

Twenty-four-hour recall

In order to overcome at least some of these problems the method that has been used in the last two major dietary surveys of adults in Australia is the 24-hour recall. This method involves the recall of all foods eaten and beverages consumed over a period of 24 hours, usually the 24 hours preceding the survey day. The information is usually collected from the respondent by a trained interviewer either at a survey centre as in the 1983 National Dietary Survey of Adults, when biochemical as well as dietary and anthropometric information was obtained from participants, or in the home as in the 1995 National Nutrition Survey when only dietary and anthropometric data were collected.

The principal advantage of the 24-hour recall is that it minimises the demands made on individuals and is widely acceptable. This is particularly important in national studies to ensure that, as far as possible, those who participate are representative of the population as a whole. The principal limitation of the 24-hour recall is that it provides information for each individual for only one day. For most individuals one day is unlikely to be characteristic of their intake in the longer term and for this reason it is not possible to use the data from surveys which use this method to classifY individuals in terms of the nutrient adequacy of their diet or to relate the 24-hour recall data from an individual to his or her health status. The method, however, can provide important information about the average intakes of different sub-groups within the population classified by gender, age, ethnic origin, income and place of residence. It can also provide the detailed information on food intake needed by ANZFA to assess the effectiveness of existing, and the need for new, food regulations.

Food frequency questionnaires

The fact that 24-hour recall data cannot provide reliable information about an individual's habitual


longer-term intake has led to the development of methods of dietary assessment which are designed to obtain information on habitual intake. The method originally developed to do this was called a dietary history because it attempted to establish not only what was eaten yesterday but also how this varied from day to day and week to week. While this approach is suitable for studies of small numbers of well-motivated volunteers it is not suitable for population-based studies involving hundreds or nuybe thousands of subjects. The main reasons for this are the fact that a dietary history interview may take an hour or longer to complete and is expensive in terms of interviewer time. Second, respondents need to be able not only to describe their diet in the detail necessary but also be prepared to devote the time and effort required. Food frequency questionnaires largely overcome the first of these problems. Basically a food frequency questionnaire is a list of foods against each of which the respondent is asked to indicate the frequency with which he or she usually consumes the food. Sometimes the individual is also asked to estimate the amount that is usually consumed either in relation to a reference serve size given in the questionnaire, or in relation to one or more illustrations of commonly consumed amounts. The length of the food list varies with the specific purpose of the questionnaire but if the object is to obtain an estimate of the total diet then the list usually contains between 100 and 150 foods. In Australia food frequency questionnaires have been used in a large number of studies including the 1985 and 1990 Victorian Nutrition Surveys (CS IRQ 1993). The main problem with the food frequency approach is that it is at best only semi-quantitative and cannot provide the level of descriptive or quantitative detail provided by 24-hour recall data and by records of food intake. To a large extent the results obtained are also dependent on the ability of individuals to provide reliable data on their long-term average intake and on the reference serve sizes and the nutrient values assigned to the food categories in the questionnaire.

Records of food intake

For the respondent, this method of measuring food intake is undoubtedly the most demanding, particularly if all food is weighed and not simply recorded in terms of standard household measures. Because the method is

so demanding, the length of time for which information can be collected is limited. Usually the maximum period of time is seven days, but in many studies the number of consecutive days of recording is limited to three or four to minimise subject fatigue. In the 1985 National Dietary Survey of Schoolchildren, records were kept for only one day and amounts recorded in terms of dimensions and common household measures in order to maximise the response rate and to prevent loss of interest in the task.

Until recently weighed food records have been regarded as the 'gold standard' mainly because they do not rely on memory either for what is eaten or for the estimation of portion size. It is now recognised that while the method can provide an accurate estimate of what is actually eaten during the period of recording this may not represent habitual food intake. The tendency is for individuals either to eat less than usual or to simplifY their diet in other ways. As a consequence, when energy intakes measured by this method have been compared with measurements of energy expenditure obtained by the doubly-labelled water method, or with the amount of food required to maintain body weight, it has been found that on average the method frequently underestimates usual food intake by as much as 20%. This is an important observation and has led to the practice of expressing energy intakes measured by any dietary method in terms of the individual's estimated basal metabolic rate. If energy intake is expressed in terms of basal metabolic rate a value of less than 1.35 is highly unlikely to represent usual intake, although it may represent intake during the period of the dietary study. An average value of 1.55 is considered to be typical of sedentary adult groups, but for those engaging in regular physical activity the value is more likely to lie between 1.6 and 1.8. While the comparison of reported energy intake with estimated basal metabolic rate does not solve the problem of underestimation of food intake, it enables plausible intakes to be separated from those that are clearly underestimates. This is particularly important when food intake data are used to assess dietary adequacy in individuals or groups.

In general, self-reports of food intake are subject to underestimation.

Chapter 10 Contemporary food use: Food supply and food intake • 16 -1

FOOD INTAKES OF AUSTRALIANS

National studies

The most recent nationally representative survey of the food intake of Australians is the 1995 National Nutrition Survey (1995 NNS). The 1995 NNS was conducted on a sub-sample of 13 858 participants in the 1995 National Health Survey from all States and Territories who were studied in all seasons and on all days of the week. Each participant provided a 24-hour recall of all food and beverages consumed on the previous day, most also completed a non-quantitative food frequency questionnaire and provided additional information on food habits (ABS 1998b; Rutishauser 2000). Measurements were also made of height, weight, waist and hip circumference and blood pressure. Because the survey was based only on one day's intake for individuals, the data cannot be used to derive information about the intakes of individuals. This is because intake varies from day to day and for most people one day's intake is not characteristic of their intake in the longer term. The 1995 NNS does, however, provide valuable information on the average intake of energy and nutrients and of the foods that are the major sources of energy and nutrients for the Australian population and for major sub-groups within the population characterised by age, sex, country of birth and place of residence. Detailed results from the survey have been published (ABS 1997, 1998c and 1999).

An obvious question of interest is whether there have been significant changes in food and nutrient intake between the previous national surveys conducted in 1983 and 1985 and that conducted in 1995. While direct comparison of the published data is possible, it is likely to be misleading because of differences m a number of survey characteristics including:

sample characteristics (age, location, season, day of week);

2 the methods used to collect and classify food intake data;

3 the food composition database used to derive nutrient intake;

4 demographic changes over time; 5 non-response and response bias.

Because sampling and other methodological differences may contribute to observed differences in the published data for food and nutrient intake

between the 1995 and the 1983 surveys, it is important to be aware of such differences and where possible to take them into account when assessing trends over time. Table 10.3 illustrates some effects of differences in survey design and methodology that can influence the interpretation of trends over time.

The first two columns illustrate the effect of adjusting the 1995 data to allow for sampling differences between the two surveys. Column 1 shows the published data from the 1995 survey and column 2 data derived for a subset of the 1995 survey sample which matches the age, geographic, season and day of week characteristics of the 1983 sample. While the differences are small for many types of foods there are also some important differences. For example the 1983 matched subset consumed a smaller amount of alcoholic beverages and more cereal and cereal products. This is likely to be because the 1983 survey excluded intake on Fridays and Saturdays and because it was carried out mainly during the winter months.

Columns 2 and 3 illustrate some differences associated with the way that foods were coded in the two surveys. The large difference in intake of nonalcoholic beverages in the 1995 NNS is mainly a consequence of the fact that the 1995 survey included an additional question about plain drinking water that was not asked in 1983. In the 1995 published data plain drinking water was included under non-alcoholic beverages and accounts for virtually all of the observed increase. Other differences that stand out in Table 10.3 are the increase in cereal-based products and dishes and the decrease in fruit intake between 1983 and 1995.

Both are to some extent artefacts due to differences in food classification and coding between the two surveys. For example in 1983 savoury 'takeaway' foods such as meat pies, Chiko rolls, dim sims, hamburgers and pizza were allocated to the meat and meat products group whereas in 1995 they were allocated to the cereal-based foods group. Similarly, the decrease in fruit intake between 1983 and 1995 results mainly from the fact that in 1995 all fruit in fruitcakes, biscuits and pies was allocated to the cereal-based products group and not to the fruit group whereas this was not the case in 1983.

Surveys carried out in Victoria in 1985 and 1990 are likely to be more informative in assessing true trends in food intake since the data are directly comparable over time, having been obtained with the same dietary methodology and the same food composition


Table 10.3 Food intake (gjday) by major food group in 1995 for all adults and for a subset of the 1995 sample with the same characteristics as the 1983 survey sample

1995 1995 1983 All adults Subset comparable Adults aged 19 with 1983 25-64

Group Major food group years and over sample years*

males non-alcoholic beverages 2052 1930 (1141) cereals & products/dishes 250 271 225 cereal-based products/dishes 154 164 (50) fats & oils 15 14 23 fish & seafood products/dishes 29 30 21 fruit & fruit products/dishes 141 139 (174) egg products/dishes 16 14 22 meat, poultry & game products/dishes 200 205 (246) milk products/dishes 322 324 318 soup 52 63 74 seed & nut products/dishes 5 5 7 vegetable products/dishes 283 284 292 legume & pulse products/dishes 12 15 6 snack foods 4 4 2 sugar products & dishes 23 22 28 confectionery & health bars 9 9 7 alcoholic beverages 410 369 457 Total food and beverages 3977 3862 3093

females non-alcoholic beverages 1917 1904 1069 cereals & products/dishes 181 192 149 cereal-based products/dishes 100 111 (41) fats & oils 10 9 15 fish & seafood products; dishes 23 26 17 fruit & fruit products/dishes 146 133 (182) egg products/dishes 11 11 16 meat, poultry & game products/dishes 116 115 (138) milk products/dishes 258 245 259 soup 58 80 58 seed & nut products/dishes 4 3 5 vegetable products/dishes 235 229 235 legume & pulse products/dishes 8 10 4 snack foods 3 3 1 sugar products & dishes 15 15 18 confectionery & health bars 9 9 7 alcoholic beverages 102 100 101 Total food and beverages 3196 3195 2315

* Figures in parentheses are not directly comparable with data for the same food group in 1995 Source: CDH 1986; ABS 1998c; ABS 1999

database (CS IRQ 1993). The greatest proportional change observed between these two surveys was a virtual doubling of rice and pasta intake (Figure 10.4). In contrast, average intake of other foods recommended by the Dietary Guidelines for Australians (bread, breakfast cereals, vegetables and fruit) differed little in 1985 and 1990. Intake of spreads (butter and margarine) and sauces decreased by about 10% between 1985 and 1990, while intake of confectionery and

baked goods increased by 10% to 20%. Overall, energy intake was only slightly higher in 1990 than in 1985. While there were only small shifts between 1985 and 1990 in the level of consumption for the major food groups, the Victorian surveys did indicate changes in the types of spreads and milk consumed in line with recommendations for a reduction in the intake of saturated fat (Figure 10.5).


Breads and crackers mean intake in g

Breakfast cereals mean intake in g

Pasta and rlce mean intake in g

9 160

12()

80

40

0 Male

9 30

20

10

0 Female

Vegetables mean intake in g

Male Female

9 50

40

30

20

10

0 Male

Fruit and juice mean intake in g

Female

• 1985

• 1990

Male Female Male Female Figure 10.4 Average intake of cereal foods, fruit and vegetables (grams per day) in VIctoria 1985 and 1990 {CSIRO 1983)

Reliable trends in food intake over time can only be established from data collected using the same survey design and food intake methodology.

Differences, attributable to country of birth, in the major groups of foods that contributed to the energy intake of Australian adults in the 1995 National Nutrition Survey are shown in Table 10.4. It is evident from this table that there are important region of birth differences in the types of foods that make up the Australian diet. Australians born in East Asia still consume more than twice the quantity of cereals and cereal products than do Australians born in Australia or in Europe but rather less fruit and vegetables than these groups. Their intake of alcoholic beverages, fats and oils and of sugar products and confectionery, however, is markedly lower than that of Australians born either in the United Kingdom and Ireland. These differences

have not changed appreciably since 1983. The food intake of Australian children is described in Chapter 21.

FACTORS INFLUENCING RECENT CHANGES IN FOOD USE

There are clearly many reasons why patterns of food use change over time. The role of historical, cultural and, more recently, technological factors on the food supply are discussed in Chapters 1 to 8 of this text. The impact of technological advances on food production, processing, storage and transport has become particularly evident in recent years, not only in terms of the much wider range of fresh foods which is now available throughout the year, but also in terms of the apparently ever-increasing range of processed food products from which the consumer is able to choose.

While technological advances have made this variety possible, the kinds of products that are available, however, also reflect changing consumer demand. That


%using

60

so 40

30

20

10

slices 30

20

Type of fat spread used

men • 19135

• 1990

20

Milk type used on breakfast cereals

• men1985

• men1990 women1985

• women 1990

Whole milk Reduced fat! skimmed milk

Average number of slices of bread eaten per week

White

• men 19135

• men 1990 women 19135

• women 1990

Brown Wholemeal

Low salt poly marg

Polyunsat marg

%using

60

50

40

30

20

10

0

slices

100

Type of fat spread used

women • 1985

• 1990

20

Milk type used in tea/coffee

• men 19135

• men 1990 women 1985

• women 1990

Whole milk Reduced tat/ skimmed milk

% of respondents eating this type of bread

• men 1985

• men 1990

White Brown Wholemeal

Figure 10.5 Changes in the type of fat spread, milk and bread consumed in Victoria in 1985 and 1990 (CSIRO 1993)

demand, in turn, is influenced by changing social and economic circumstances as well as by scientific knowledge. For example, the broad range of convenience foods and pre-prepared meals that is now available has its origins in the changing patterns of family and social life and, in particular, on the effect these changes have had on the working patterns of

women. These changes have meant not only that many women now have less time for food preparation than in previous years, but also that other family members have a greater role in food selection and preparation.

The fact that the Australian consumer has access to several varieties of milk and many different types of bread and other basic foods is not only a consequence


Table 10.4 Mean intake of foods from some major food groups by Australians by region of birth (g per person per day)

Food group Australia

cereals & cereal products 197 cereal-based products & dishes 130 fruit products & dishes 138 vegetable products & dishes inc. legumes 269 meat, game & poultry products 157 milk products & dishes 295 fats & oils 13 sugar products & confectionery 29 alcoholic beverages 269

Source: ABS 1999

of advances in food technology but also of the information explosion. This has meant that an enormous amount of information on nutrition has become readily accessible to the general public through the media. In addition, medical and public health professionals have become more aware of the importance of long-term food habits on health status in later life. As a result, food habits and eating patterns have become a major focus for the whole community. They have further stimulated development, by the food industry, of new products which address public and/ or professional concerns about the effects of individual components of food on health or which are intended to make up for overall dietary inadequacies or excesses which arise for reasons beyond the individual's control.

Another major influence on current food patterns is the multicultural nature of Australian society. Migrants to Australia have brought with them their

Region of birth UK, Ireland & Other parts New Zealand of Europe East Asia

212 222 530 122 114 100 131 218 152 291 256 212 151 155 181 312 251 227

12 9 6 31 22 19

266 213 67

national cmsmes and publicised them to the wider community by setting up restaurants and take-away food outlets. The outcome is that in Australia's capital cities it is now possible to sample national and regional cuisines from all over the world. In turn, the existence of these establishments has created a market for the importation and, in some cases, the local production of the ingredients required for their preparation. A diverse range of convenience and other packaged goods based on the cuisines of other nations are consequently now available from supermarkets as well as from specialist shops and the corner delicatessen. While the range of foods available outside metropolitan areas is clearly less varied than that in capital cities, few Australian country towns are now without one or more food outlets that specialise in cuisines of Southern European or Asian ongm.

NUTRITION MONITORING

Information about the nutritional environment and its impact on the population IS also needed by governments to answer a number of important questions that include:

• Is the food supply adequate to meet the nutrient needs of the population?

• Is the food supply safe to consume? • Is an adequate food supply accessible to all

segments of the population? • Is there any evidence of nutrition related

problems?

Answers to these questions have important implications for govermnent policy in relation to domestic agricultural and livestock production, food imports and exports, development of food standards and other regulations in respect of food safety, and the allocation of resources, both financial and human, to health and welfare services. The main types of information generally used by governments to answer the above questions are outlined in Figure 35.1 (WHO 1991).

FOOD SUPPLY DATA

It is evident from this figure that a good deal of reliance is placed on information about the food supply and food intake. Such information does not measure the 'nutritional status' of the population, but provides an indication of the population's nutritional environment and thus of the nutritional problems likely to be encountered. In Australia, food supply data are obtained

Chapter 35 Nutrition assessment and monitoring • 499

Food chain Data sources

food supply 11-------1.- food balance system I sheets

food consumption t----___,~ dietary surveys

I I household surveys

system I food prices

health impact

mortality data morbidity data

t----___,•~ anthropometric data birthweight data infant feeding practices

Figure 35.1 Primary sources of data for a nutrition

information system (Kelly cited in WHO 1991)

primarily from the Apparent Consumption (!f Foodst1ifjs Australia series which is produced by the Australian Bureau of Statistics by collating data from agricultural and livestock production statistics and manufacturing census data (ABS 2000). The limitations of these data are discussed in Chapter 10. Their primary value lies in the fact that they provide information on long-term trends in the availability of the major commodity groups such as grain and dairy products, meat and meat products, fruit and vegetables, sugars and beverages. Figures 35.2, 35.3 and Figure 10.3 in Chapter 10 show different ways in which food balance (apparent consumption) data are used. Figure 35.2 illustrates differences in per head energy and protein supply in different parts of the world and provides an indication of the types of nutritional problems likely to be found in different countries. Countries, such as Australia, in which the available energy supply is 12 000 kJ (3000 kcal) or more per head per day are those in which obesity and ischaemic heart disease are common. In contrast, in countries in which the available energy supply is less than 8000 kJ (2000 kcal) undernutrition is widespread. Differences exist also in the types of food that provide the energy. Figure 35.3 shows how, as national income increases (expressed as gross domestic product), the percentage of total energy derived from sugar and fat also increases and the percentage of total

500 • Part VI Food, individuals, environment and policy

MJ/hd/day

Australia

North America

Western Europe

South America

Central America

Japan

China

Africa (south of Sahara)

North Africa

India

Bangladesh

~ Animal protein 15 10 5 0 25 50 75 100

Figure 35.2 Amounts of energy and protein available per head per day in different countries

energy derived from starch decreases. Several diseases common in affluent countries have been linked with high fat and sugar intake and a reduced intake of carbohydrate in the form of starch.

FOOD PRICES

The principal use of data on food prices in the context of nutritional monitoring is as a means of assessing trends in the relative affordability of various food items over

Correlation based on 85 countries

r;H''i;l Separated edible fats

D Unseparated vegetable fats

D Unseparated animal fats

• Various carbohydrates (starch)

D Sugar

• Animal proteins

Vegetable proteins

Q)

E 8 .!: n; I: 0

~ z

time (Lester 1994) and thus in their accessibility to different segments of the population. The indicator used to describe trends in food and other prices is the Consumer Price Index (CPI). The CPI is based on the cost of a 'basket' of goods and services that represents a high proportion of the overall expenditure of metropolitan wage and salary-earner households. Because the CPI, for structural and practical reasons, does not take into account the expenditures of households in nonmetropolitan areas, or of households whose income is derived mainly from pensions and allowances, it is not

0 Percentage of energy 100

Figure 35.3 Proportion of dietary energy derived from different types of food (Perisse et al. 1969)

directly relevant to rural and low-income households. Because rural and remote households are likely to pay higher prices for foods and because low-income households expend a higher proportion of their income on food than other households, more specific expenditure data for both groups are needed to determine the influence of changes in food prices on the affordability of a nutritionally adequate diet by such households.

HOUSEHOLD SURVEYS

Household budget or expenditure surveys are widely used by governments not only to provide data on expenditure, including expenditure on food, but also to provide information on the relative quantities of different types of foods purchased by different kinds of households (WHO 1991). In Australia, a Household

Expenditure Survey (HES) is conducted at five-yearly intervals by the Australian Bureau ofStatistics.The HES does not currently include information on food quantities. The reason for this is that the principal purpose of the HES is not to provide data for nutrition monitoring but to provide weighting factors for the Consumer Price Index. Relatively minor modifications to the existing survey methodology would, however, permit information to be obtained which would make it much more useful for national nutrition monitoring. For example, food purchasing patterns could be monitored in relation to current dietary recommendations at regular intervals, not only for the population as a whole but also for different types of households categorised by income, geographic location and composition.

DIETARY SURVEYS

The information available from dietary surveys in Australia is described in detail in Chapter 10. Nationally representative dietary surveys are expensive to conduct, partly because large numbers of subjects are involved and partly because a national survey involves major costs for travel and accommodation to interview respondents who live in rural and remote parts of the country. The 1995 National Nutrition Survey cost in excess of $3 000 000. Detailed data on food intake, such as the data provided by the 1995 National Nutrition Survey, are used by regulatory bodies such as the Australia and New

Chapter 35 Nutrition assessment and monitoring Ill 501

Zealand Food Authority in a number of ways; for example, to determine the likely impact of changes to food regulations, and to establish the levels of food additives and contaminants in the food supply which do not pose an unacceptable level of risk to 'high consumers' of specific food products. They are also used to assess the need for, and likely impact of, fortification of foods with nutrients such as folic acid on different segments of the population. The data from national dietary surveys also enable Commonwealth and State departments of health to assess the extent to which the diets of different segments of the Australian population meet current dietary recommendations and thus to assess progress towards national goals and targets for the frequency of core cereal and fruit and vegetable consumption and for recommended levels of intake of fat, iron and calcium.

MORTALITY AND MORBIDITY DATA

Mortality and morbidity data provide information on the diseases and conditions that are reported as causes of death or which require admission to hospitals. In some instances data are also available for chronic conditions such as cancer and diabetes from population based disease registers. The data from such collections reflect the major social and health problems of the community and can be used both as clues to the most likely causes of mortality and morbidity in a population and as measures of the prevalence of specific nutrition related conditions in the population. Table 35.6 shows standardised mortality rates from selected diet related diseases for the period 1981-91 compiled by Jain (1994)

Table 35.6 Mortality from selected diet-related diseases, proportion of all deaths in 1993 and percentage change in age-standardised mortality rate over the period 1981-91

Change in Proportion of all mortality rate

deaths in 1993 (%) 1981-91 (%)

Condition Males Females Males Females

ischaemic heart disease 25.1 23.8 -31.8 -21.8 cerebrovascular disease 13.0 10.0 -42.7 -42.7 cancer of colon 2.6 2.8 1.8 -12.7 cancer of stomach 1.2 0.8 -34.5 -31.8 cirrhosis of liver 1.1 0.5 -25.5 -28.2 diabetes mellitus 2.0 2.3 6.4 -5.5

* Mortality rate age standardised to the Australian population at

30 June 1988


from routinely collected data on mortality. During this period there was a significant drop in age standardised death rates for all causes of death which was due primarily to a fall in death rates from cerebrovascular and heart disease. Despite this fall cardiovascular disease was still the m~or contributor to the burden of disease (years of life lost) (YLL) and years lost due to disability (YLD) in Australia in 1996 (Figure 35.4).

Whether the marked changes for heart and cerebrovascular disease are mainly attributable to changes in risk factor status (including diet), to earlier identification or to better treatment and management of these conditions or to as yet unidentified factors, is still a matter for debate. An estimate of the burden of disease, assessed in terms of DALY s (disability adjusted life years) attributable to ten major risk factors in Australia in 1996 ranked physical inactivity, alcohol, obesity and lack of fruit and vegetables among the top six contributors (Table 35.7).

Disability adjusted life years (DALYs) are the years of life lost due to premature mortality and disability and measure the number of healthy years of life lost as a consequence of death or newly diagnosed disease or injury in the population.

Table 35.7 Burden of disease attributable to ten major risk factors in Australia in 1996

Percentage of total DALYs Risk factor Persons Males Female

tobacco 9.7 12.1 6.8 physical inactivity 6.7 6.0 7.5 high blood pressure 5.4 5.1 5.8 alcohol harm 4.9 6.6 3.1 alcohol benefit -2.8 -2.4 -3.2 obesity 4.3 4.4 4.3 lack of fruit and vegetables 2.7 3.0 2.4 high blood cholesterol level 2.6 3.2 1.9 illicit drugs 1.8 2.2 1.3 occupation 1.7 2.4 1.0 unsafe sex 0.9 1.1 0.7

Source: Mathers et al. 2000

Morbidity and mortality data, like food supply and food intake data, only provide indirect measures of the kinds of nutritional problems most likely to be encountered in a population. This is because virtually all of the diet related conditions encountered in developed countries like Australia have a multi-factorial aetiology of which diet is only one possible contributory factor and not a necessary cause. The mortality rates from, and prevalence of, such conditions thus do not provide a direct measure of the prevalence of nutritional disease

Cardiovascular~··············••c==:J 21.9%

Cancerl•••••••••••••••r===:J 19.1%

Diabetes

Infectious

Digestive

Genitourinary

0

9.4%

8.4%

7.1%

3.6%

3.0%

3.0%

2.6%

2.5%

100 200 300

13.3%

400

D YLD • YLL

% of total disability affected life years

500 600

Disability affected life years (DALYs) (in thousands)

Figure 35.4 Burden of disease for major disease groups, Australia 1996 (Mathers et al. 2000)

in the same way as does the mortality from protein l'!1ergy malnutrition or the prevalence of blindness resulting from vitamin A deficiency, for both of which there is a direct and necessary nutritional cause.

Differences in diets and disease patterns between developing and Western industrialised countries suggest that dietary changes might be an important means of preventing the diseases of affiuence, but other factors, such as genetic make-up, infections, smoking and the level of physical activity must also be considered. It is also important to see today's health problems in perspective. Expectation of life in Australia today is more than half as long again as it was only 100 years ago, that is 75.2 and H 1.1 years for males and females respectively in 1994-96 as against 4 7 and 51 years in 1885.

ANTHROPOMETRIC DATA

The anthropometric measures most commonly used for national nutritional surveillance are body weight and height and various indices derived from them such as the body mass index (weight corrected for height by dividing weight in kilograms by height in metres squared). Measurements such as weight and height are widely used in population studies because they provide an overall measure of nutritional status, are non-invasive, quick to carry out and require only minimal equipment. Weight and height data for a population can provide information about the growth of children and about the prevalence of obesity or underweight in the community. In adults the prevalence of obesity is associated with the prevalence of a number of other diseases including diabetes, hypertension and ischaemic heart disease. In children, growth is regarded as an important indicator of nutritional status since children who are ill or who do not have enough to eat do not grow properly. Figure 35.5 shows the interruption in the long-term secular increase in height of Japanese schoolboys during World War II at a time when conditions were less favourable, and illustrates the sensitivity of growth rate as a measure of health and nutritional status in children. While environmental factors other than food and nutrient intake, such as illness and social conditions, clearly also influence growth, they often exert their effect by influencing food and nutrient intake or utilisation.

Height for age, weight for age and weight for height are the measures most frequently used to assess growth

Chapter 35 Nutrition assessment and monitoring 11111 503

140

135

130

125 / 120

1900 1920 1940 1960

Figure 35.5 Secular trends in height of nine- and eleven

year-old-schoolboys in Japan (Takahashi 1966)

in children. Somewhat surprisingly there is no regular source of information on the weight and height of Australian pre-school children. However, weight, and often also length, is routinely measured at birth and, in most States, at various times during the pre-school period and at the time of school entry. Compilation of these data on a regular basis would provide valuable information on trends in growth rates and the prevalence of obesity and undernutrition in childhood. Table 35.8 shows changes in the mean weight and height of New South Wales schoolchildren since the early part of this century together with data from the 1985 Australian Health and Fitness Survey (Pyke 1987) and from the 1995 National Nutrition Survey (ABS 1998). The increase in height and weight between 1915 and 1985 probably reflects improvements in a range of environmental factors including better living conditions, control of infection and access to food whereas the increase between 1985 and 1995, particularly that in weight at ten and fifteen years of age, is more likely to reflect the trend towards earlier maturity as well as a decline in the level of physical activity in this age group.

For Australian adults (25 to 64 years) there are data on measured weight and height from a series of National Heart Foundation Risk Factor Prevalence Surveys (RFPS) carried out in Australian capital cities between 1980 and 1989 and from the 1995 National Nutrition Survey. The data from these surveys suggest that the weight, but not the height, of young Australian adults increased considerably during this period (Table 35.9); the mean body mass index increased by between


Table 35.8 Secular increase in height and weight of schoolchildren in Australia between 1915 and 1995

Mean height (cm)

Age in years: 5 10

Boys 1915 108 133 1937 111 137 1954 112 139 1970 112 139 1985 141 1995 114 142

Girls 1915 107 132 1937 109 136 1954 111 139 1970 111 139 1985 141 1995 113 143

Sources: Jones et al. 1973; Pyke 1987 and ABS 1998

two and three units for men and women m all age groups. The proportion of the population aged 25 to 64 years of age with a measured body mass index between 20 and 25 ('healthy weight range') was 45% for men and 55% for women in the 1980 RFPS but only 32% and 41% respectively in the 1995 National Nutrition Survey. Thus, despite considerable focus on the problem of overweight, it has increased rather than

Mean weight (kg)

15 5 10 15

159 18.5 28.5 47.0 166 19.5 30.5 54.0 169 20.5 33.5 58.5 169 20.5 37.0 58.0 171 33.5 59.5 174 20.9 35.9 65.9

157 18.0 28.0 47.5 160 19.0 30.5 52.0 162 20.0 34.0 56.0 160 20.0 34.0 53.0 162 34.0 54.0 164 20.7 39.1 58.4

decreased over the last two decades. The national target for the year 2000 was 60% (see Chapter 36).

BIRTHWEIGHT AND INFANT MORTALITY

A national compilation of data on birthweight in Australia is published annually by the Perinatal Statistics

Table 35.9 Mean weight, height and body mass index for Australian adults aged 25 to 64 years of age in 1980, 1983, 1989, and 1995

Mean height in cm Mean weight in kg

Age in years: 25-34 35-44 45-54 55-64 25-34 35-44 45-54

Men 1980 177.5 175.5 174.0 173.0 75.6 78.8 77.4 1983 176.0 175.0 174.0 172.5 75.1 77.2 78.8 1989 176.0 175.5 174.5 173.0 77.5 70.0 80.4 1995 176.0 174.0 82.4 84.4

Women 1980 162.5 163.0 161.5 160.0 58.7 61.4 63.2 1983 163.0 162.5 160.5 159.5 60.4 62.5 64.8 1989 163.0 162.5 162.0 160.0 61.8 63.9 67.3 1995 162.9 161.1 67.3 71.2

Body mass index Per cent with BMI in range Age in years: 25-34 35-44 45-54 55-64 <20 20-24.99 25-29.99

Men 1980 24.2 25.5 25.8 25.8 4.8 45.4 40.6 1983 24.2 25.2 26.0 25.9 4.7 46.2 40.0 1989 25.9 25.5 26.4 26.3 3.1 41.3 44.1 1995 26.5 27.8 2.9* 32.2* 45.2* 18.5*

Women 1980 22.1 23.3 24.2 25.0 16.7 1983 22.8 23.7 25.1 25.4 14.1 1989 23.2 24.2 25.7 26.7 11.8 1995 25.3 27.4 7.9*

* Data relates to all adults aged nineteen years and over and not just to those aged 25-64 years.

Sources: Bennett and Magnus 1994; NHF Report Nos 1, 2 & 3; ABS 1998.

55.0 20.2 53.4 22.0 49.8 10.5

40.6* 28.8*

55-64

76.4 76.9 78.6

63.7 64.6 67.0

2:30

9.3 9.1

11.5

8.0 10.5 13.2

18.2*

Unit of the Australian Institute of Health and Welfare (AIHW) from data provided by State and Territory health authorities (Day et al. 1999). Average birth weight and, more specifically, the proportion oflow birthweight infants (those weighing less than 2500 g at birth) is a good index of maternal health and nutritional status both prior to and during pregnancy and an important predictor of infant mortality. The most important factors known to influence birthweight are maternal body size, infection, smoking, alcohol consumption and maternal nutrition during pregnancy. Differences in birthweight between different population sub-groups thus need to be interpreted in the light of information on these factors. In Australia in 1997 the average birth weight of live born infants was 3356 g. The percentage of low birth weight infants in the same year was 6.1% with little variation between States and Territories except for the Northern Territory (10.2%). This difference IS primarily attributable to the high prevalence of low birthweight (13.0%) in Indigenous infants. Infant mortality rates for the same year were 5.3 per 1000 livebirths for Australia, 3.8 for the Australian Capital Territory and 12.5 for the Northern Territory. These figures clearly indicate a relationship between the proportion oflow birthweight infants and infant mortality, but additional data, on maternal health and lifestyle, are needed to determine the basis for the much higher rate oflow birthweight in the Northern Territory.

INFANT FEEDING PRACTICES

The way that infants are fed, particularly in the first four to six months of life, has important consequences for their growth and development. Until early in the twentieth century, breastfeeding for the first six to nine months was almost universal and mortality from gastroenteritis was high among those infants who were fed breastmilk substitutes. In Australia, records from the Victorian Public Health Department show that between 1944--45 and 1971 the percentage of mothers who were fully breastfeeding their infants at three months of age fell from 52% to 21%. Since that time, the prevalence of breastfeeding at three months of age has again increased and has been above 50% since 1985 (Lester 1994).

While the advantages of breastfeeding are very obvious in terms of infant morbidity and mortality when appropriate breastmilk alternatives are not freely available to mothers-as in developing countries-

Chapter 35 Nutrition assessment and monitoring Ill 505

breastfeeding also has advantages in Australia today. The advantages of breastfeeding for Australian infants during the first four to six months of life are reviewed in Dietary Guidelines for Children and Adolescents (NH&MRC 1995). In 1995, 54% of infants were still exclusively breastfed at 13-16 weeks but by 25-28 weeks this had dropped to less than 20%. The corresponding proportions for partial breastfeeding were 58% and just over 40% in 1995 (Moon et al. 1998). With the exception of Victoria, collation of State-level data on breastfeeding has been, and still is, sporadic. This is despite recommendations that the Australian Government establish 'a coordinated national system whereby the rates ofbreastfeeding are collected on an ongoing basis'. A number of questions on infant feeding including questions on breastfeeding were included in both the 1988-89 and the 1995 National Health Survey (see also Chapter 19). The same questions could be used to monitor the prevalence of different types of infant feeding in other population samples in the absence of a coordinated national monitoring system.

ESSENTIAL FEATURES OF A NATIONAL FOOD AND NUTRITION MONITORING AND SURVEILLANCE SYSTEM

In order to be useful for policy purposes the data from a national food and nutrition monitoring and surveillance system should be:

• relevant to the major nutritional problems encountered;

• available to decision-makers within a reasonable timeframe;

• available on a regular basis; • collected by standard methods to enable trends

over time to be established; • presented in a way in which they are readily

understood by, and capture the interest of, those responsible for policy decisions; and

• able to address issues which have the potential to be changed by policy measures.

These requirements, together with the high costs of primary data collection, have encouraged nutrition policy-makers, in Australia and elsewhere, to rely very largely on the use of existing data collections for


monitoring the food and nutrition status of the population. The main strength of these collections for monitoring is that they provide comparable data at regular intervals and without undue delay. Their principal deficiencies lie in the fact that usually they do not provide direct measures either of the population's exposure to dietary constituents or of its nutritional status. Moreover, because of the need for comparability

over time, regular collections are not very responsive to changing conditions, such as changes in the nature and complexity of the food supply. For this reason it is necessary from tin1.e to time to conduct specific surveys, such as the 1995 National Nutrition Survey, which can provide more specific and detailed information on nutritional issues of particular concern.

SUMMARY • Information about nutritional status in individuals is used to identifY specific nutritional

conditions, to determine the need for and to assess the impact of specific nutritional measures.

• No single measure provides an overall assessment of nutritional status; information from a number of different types of measures (anthropometric, biochemical and physiological) is integrated in a nutritional assessment.

• Typically an individual's status is assessed in relation to reference values determined on the basis of carefully collected data from apparently healthy individuals of the same age, sex and ethnic group.

• Governments also need information about the food and nutrition status of the population as a whole to determine and evaluate policy in agriculture, trade, social welfare and health.

• The principal sources of data used for population level nutrition monitoring are routinely collected statistics on food supply and expenditure, on mortality and morbidity and on weight and height from health or community services records.

• The principal advantage of routinely collected data is that they can be used to monitor trends over time and to relate these to changes in diet, social and environmental conditions which may result from changes in policy.

REFERENCES

Australian Bureau of Statistics (ABS). National Nutrition Survey Nutrient Intakes and Physical Measurements Australia 1995 (Cat. No. 4805.0), ABS, Canberra, 1998.

Australian Bureau of Statistics (ABS). Apparent Consumption of Foodstuffs Australia 1997-98 and 1998-99 (Cat. No. 4306.0), ABS, Canberra, 2000.

Bennett, S.A. & Magnus, P. Trends in cardiovascular risk factors in Australia. Med J Aus 1994; 161:519-27.

Day, P., Sullivan, E.A., Ford,J. & Lancaster, P. Australia's Mothers and Babies 1997, Perinatal Statistics Series No. 9. AIHW Cat. No. PER 12. AIHW National Perinatal Statistics Unit, Sydney, 1999.

Gibson, R.S. Principles cif Nutritional Assessment. Oxford University Press, Oxford, 1990. Jain, S.K. Trends in Mortality, by Causes of Death in Australia, States and Territories during 1971-92. Joint

publication of the National Centre for Epidemiology and Population Health and Australian Bureau of Statistics (Cat. No. 3313.0),ABS, Canberra, 1994.

]ones, D.L., Hemp hill, W & Meyers, E.S.A. Height, TM?ight and Other Physical Characteristics of New South Wales Schoolchildren. Part 1. Children Aged Five Years and Over. Special Report. New South Wales Department of Health, Sydney, 1973.

Lester, I. H. Australia's Food and Nutritio11. AGPS, Canberra, 1994; 102-9. Mathers, C.D., Vos, E.T., Stevenson, C.E. & Begg, S.J. The Australian Burden of Disease Study:

measuring the loss of health from diseases, injuries and risk factors. Med J Aust 2000; 172:592-6.

Chapter 35 Nutrition assessment and monitoring • 50 7

Moon, L., Rahman, N. & Bhatia, K. Australia's Children: Their Health and vvellbeing 1998. Australian Institute of Health and Welfare. Cat. No. PHE 7. AIHW, Canberra, 1998.

National Health and Medical Research Council (NH&MRC). Dietary Guidelines for Children and Adolescents. AGPS, Canberra, 1995.

National Heart Foundation (NHF). Risk Factor Prevalence Study Reports Nos 1, 2 and 3. NHF, Canberra, 1981, 1985, 1990.

Perisse, J, Sizaret, F. & Francois, P The effect of income on the structure of the diet. FAO Nutrition Newsletter, 1969; 7:1.

Pyke, JE. Australian Health and Fitness Survey 1985. The Fitness, Health and Physical Peiformance of Australian School Students Aged 7-15 Years. Australian Council for Health, Physical Education and Recreation Inc., Adelaide, 1987.

Takahashi, E. Growth and environmental factors in japan. Human Biology 1966; 38:112. World Health Organization (WHO). Food and Health Data: Their Use in Nutrition Policy-making.

W Becker & E. Helsing (eds). WHO Regional Publications, European Series, No. 34, Copenhagen, 1991; 18.


THE HISTORY OF FOOD AND NUTRITION POLICY

A catalyst for the development of food and nutrition policies in recent times was the growing appreciation in developed countries of the links between affiuent ways of life and chronic non-communicable diseases like obesity, macrovascular disease, neoplastic disease of certain types, diabetes, osteoporosis, degenerative joint disease, alcohol related conditions and the dementias in what had become ageing societies. This led to the development of dietary guidelines. Sweden led the way with a National Farm Policy related to nutrition in 1963, and a ten-year diet and exercise program in 1971. This was a more integrated approach than that of the US Dietary Guidelines developed in 1980 jointly between the Departments of Health, Education and Welfare and Agriculture as a response to the 1977 report of the Senate Select Committee on nutrition and human needs, under the chairmanship of Senator McGovern.ln Australia, in 1979, similar guidelines were released by a multidisciplinary working party and by government (Blaxter 1986). By referring to the need for an adequate

Table 40.8 Relations between food variety and arterial

wall characteristics for healthy subjects and

people with diabetes considered together

(shown as rs which is Spearman's rank correlation coefficient)

Total Plant Food variety Food variety

Aorto-iliac artery compliance 0.38** 0.31 * Pulse wave

common femoral posterior tibial

-0.38** -0.44**

-0.31 * -0.41 **

*: p<<0.05; **: p<<0.01 as indices of statistical significance. These findings indicate that where there is more food variety, arteries are more compliant and damping of pulse waves is less, which is consistent with food variety being protective against arterial disease with atherosclerosis. Source: Wahlqvist et al. 1989

intake of water as a preferred beverage, the peculiar needs of people living in a dry and hot continent, with excesses of alcohol intake, were taken into account. This example of differences between nations in b'uidelines underscores the merits of each national government formally considering its own policy.

Chapter 40 Food and nutrition policies in the Asia-Pacific region: Nutrition in transition • 583

Dietary goals, guidelines and policies

A national food and nutrition policy may be defined as a statement of intent about governmental action to achieve nutrient or dietary goals, explicitly taking into account the relationship between diet and health. A nutrient or dietary goal is defined as the range of nutrients or foods in which population average intakes are judged to be consistent with a low prevalence of diet related diseases in the population, for example, total average carbohydrate for a population should be between 55% and 75'/{, of energy. Dietary guidelines express the goals in terms of foods (or combination of foods) which are to be eaten by individuals. For example, the carbohydrate goal would be expressed in a dietary guideline as: eat more bread and cereals (preferably wholegrain), vegetables and fruits. Guidelines do not have to be quantified but need to be based on goals. Many different dietary patterns can be compatible with a given set of dietary goals. However, dietary guidelines have the potential to be misinterpreted and may result in 'unexpected consequences'. For example, in Australia a major contributor to increased fruit consumption has been an increased consumption of fruit juice (Baghurst et al. 1987). The loss of physicochemical properties of fruit in the production of fi-uit juice may lead to significantly different metabolic profiles for glucose and insulin (Heaton et al. 1979).

Food and nutrition policy is usually the business of governments, be they national or provincial, and of international agencies like WHO, FAO and UNICEE The specificity and emphasis of a country's food and nutrition policy objec.tives will vary with the existing food and health situation, for example whether the country is a net importer or exporter of food or whether malnutrition, overnutrition or both is the problem. Dietary goals and guidelines have most impact on people's lives when they are incorporated into policies, nutrition education handbooks, food labelling, modified foods and health claims. There is a big difference between a government report that induces no action and a policy that is followed through and supported with education, subsidies and tarifE.

Food and nutrition policy addresses the following ISSUes:

Food security (a dependable and safe food supply). The primary objective of national food and nutrition policy has been and continues to be to obtain a secure, safe and sufficient food supply.

A reliable food supply has been described as a prerequisite for all other activities of humans (Blaxter 1986).

2 Health and well-being as far as they can be met by the food supply and food intake. (Many countries in the Asia-Pacific region are undergoing an epidemiological transition, in which disease profiles are emerging that result from both under and overnutrition).

3 The ecological impact of food production, processing, storage and transport.

When such policy was in development m Australia, certain specific objectives were identified in support of the above general requirements (CDCSHH 1992). These included the following:

To produce food locally as far as possible. This reduces energy costs and also gives people a greater sense of control of their food supply. Urban gardens were seen as part of such a policy, and work was done on this as part of the Victorian Food and Nutrition project in Melbourne. The preservation of local food culture can also be increasingly important in an age where cultural internationalisation and loss of diversity are occurring. On the other hand, there is value in moving food from one locality to another if it adds to diversity and reduces the risk of local nutrient deficiencies or of food component excesses and toxicities.

2 To assist food-deficit countries to achieve a satisfactory local food production and, where necessary, to produce additional food within Australia (or any other country) to make good food shortages. It is now generally agreed that continuing food aid does little, beyond alleviating food crises, to deal with food deficits (Ramalingaswami 1994).

Policy of this kind requires the participation of several sectors including agriculture, food manufacturing, health, education, finance and economics at the most senior levels of government such as cabinet, at the professional level, and at the community organisation level. The nature and scope of modern public health policy were defined and promulgated by WHO in the 1980s through its Health For All strategy (WHO 1981) and Healthy Public Policy movement (WHO 1986). These key developments emphasised the following factors:


intersectoral planning and management; 2 equity in health outcomes; 3 a population-wide setting; 4 a prevention focus.

This range of factors was later extended to include an ecological dimension. Management and planning of policy has also been required. The food system is large and complex and nutritional health is just one outcome. As one commentator has noted, 'The food system, in reality, is not driven by nutritional, but market and competitive needs' (Tansey 1994). Thus, while the purpose and outcomes expected of food and nutrition policy are oriented towards nutritional health, there are a variety of different stakeholders critical to its successful implementation. In particular, there is a need to adopt an intersectoral focus to the management and planning of policy. In addition, the management and planning of food and nutrition policy issues extends across all levels of government, from national to local, to address issues of food availability and accessibility. The Plan of Action of the World Declaration of Nutrition adopted by ministers of 159 states at the FAO/WHO International Conference on Nutrition, Rome 1992 (FAO/WHO 1994), states as the first of the strategies 'incorporating nutritional objectives, considerations and components into development policies and programmes'.

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