4a macronutrients and micronutrients_ non nutrient food ingredie

8/3/2019 4a Macronutrients and micronutrients_ non nutrient food ingredie

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National Food Policy Capacity Strengthening Programme (NFPCSP)

INTENSIVE TRAINING COURSE ON FOOD AND NUTRITION: PRINCIPLESAND POLICY APPLICATIONS

Module 2: Food, Nutrients and Their Functions

Lecture 4. Macronutrients, Micronutrients and Non-nutrient Food Ingredients of Health Significance

byDr. Harun K.M. Yusuf

National Utilization (Safe and Nutritious Food) Advisor, NFPCSP


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What is Food and what is Nutrition?Food is any edible material that supportsgrowth, repair and maintenance of the body.Food also protects the body from infectionsand diseases.Nutrition is the process by which body utilizesfood for growth and maintenance and healthyliving.Food functions in the body through thenutrientsit contains


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What are nutrients?Nutrients are substances found in food. These are: Carbohydrate Fat/Oil Protein Vitamins Minerals

Since Wateris indispensable for life, it isconsidered both as a food and as a nutrient.Dietary Fibreand somePhytochemicalsof plant

foods, although not nutrients as such, are needed forgood

health.


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What food does in the body does through the

nutrients it contains. The body utilizes thesenutrients to grow and keep healthy and strong.All nutrients needed by the body are availablethrough food.

No food by itself (except for breastmilk which is

adequate for babies up to six months of age) hasall the nutrients needed for full growth andhealth. Food therefore must be balanced.

We therefore need a variety of foods to get all

the nutrients the body needs.


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Each nutrient has its own function in the body.Specific nutrients do their best work in the bodywhen present with other nutrients.

Nutrients are therefore mutually supportive.


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What are Macronutrients and Micronutrients?The nutrients can be divided into two majorgroupsMacronutrientsand Micronutrients.Macronutrients are those that are needed in largequantities (tens or hundreds of grams) every day.

These are: Carbohydrates, protein and fats/oils.

Micronutrients are those that are needed inminute quantities (micrograms or at bestmilligrams). These are vitamins, minerals andtrace elements.


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Carbohydrates

Main function is energy production in the body.Largest source of energy: 40 - 80 percent of thetotal energy intake in different countries.Neither extreme is good. The ideal contributionis 60 percent.One gram of carbohydrate provides 4 Kcal.Grains (rice, wheat, maize), roots and tubers(potato, sweet potato, guam, banana) andlegumes (pulses, nuts) are rich sources of

carbohydrates.


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Sweet fruits and some vegetables also provide

carbohydrate in the form of sugar.Milk sugar is lactose.Honey has high content of fructose, thesweetest of all sugars.Soft drinks contain sugar but almost no other

nutrients.


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Carbohydrates are present in two

forms:

Simple carbohydrates: glucose, fructose,sugarCompound carbohydrates: starch inplants and glycogen in animals (liver andmuscles)Compound carbohydrates are polymers of

glucose.


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Carbohydrates and sugarsDigestion in the intestine

Glucose (plus other monosaccharides)Absorbed into blood

In presence of insulin

Taken up by cellsIn presence of O2

Metabolized to CO2 + H2O + Energy(no side effects in glucose use in the body)


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During well-fed conditions, body glucose isstored in liver and muscles as glycogen, a

compound carbohydrate. Glycogen is thereforethe animal counterpart of plant starch.During starvation, glycogen of liver and muscle isbroken into glucose to provide energy.Glucose is the only metabolic fuel for the brain

under normal conditions.Carbohydrates taken in excess of energyrequirements are directly converted into fat anddeposited in the body.


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ProteinProtein is the building material for all body parts,such as muscle, brain, blood, skin, hair, nails, bonesand body fluids.

It is essential for growth, repair of worn-out tissues,replacement of used-up blood and resistance againstinfections.Protein comes from both animal and plant foods.Meat, fish, egg, and milk and milk products are richsources of animal protein.Pulses, nuts and beans are rich sources of plantprotein.Cereals are low in protein (e.g. rice: 6

8%, wheat: 12 14%), but because of their large quantities in the

diet, they meet a major portion of total dietary proteinrequirement.


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Animal proteins are of high quality (first-classproteins) because of their more complete andbalanced composition of amino acids.Plant proteins are of lower quality (second-classproteins) because they are incomplete in one or

more of the essentialamino acids.Combination of two or more plant foods canmutually supplement each others deficiency andtherefore give rise to high quality protein. Forexample, khichuri,which is a mixture of rice and

dal(pulse), is a good quality diet.


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The protein from beans and legumes are ofbetter quality than the protein from rice andwheat products. These foods are consideredless expensive meat substitutes and are often

called the poor mans meat.Potato is poor in protein (


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Proteins are polymers of smaller units calledamino acids, some of which can bemanufactured in the body (so-callednon-

essential), and others must be provided pre-formed by food (theessential amino acids).


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ProteinDigestion in the

gastro-intestinal tractAmino acidsAbsorbed into bloodTaken up by the cells

Synthesize body proteins


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Although the main function of protein is

to build and maintain the body, it alsogives energy.One gram of protein gives 4 Kcal.


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Fats/Oils

Fats/oils are concentrated sources of energyneeded by the body.The term fat is commonly used to refer to afamily of compounds called lipids which arewater-insoluble.

They include triglycerides, phospholipids andsterols such as cholesterol. Triglyceridespredominate both in the food and in the body.1 gm of fat provides 9 kcal, i.e. more than double

the energy given by carbohydrate or protein perunit weight.


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Chemically, triglycerides are fatty acid tri-esters of

glycerol:H2C O CO fatty acid

HC O CO fatty acid

H2C O CO fatty acid


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FatsA triglyceride may be a FAT or OIL, dependingon the predominant type of fatty acids it

contains: saturated, monounsaturated andpolyunsaturated.When predominant fatty acids are saturatedand monounsaturated, then it is solid at roomtemperature and is termed as FAT.


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Usually, triglycerides of land animal sources areFATs.Examples are fats of beef, mutton, goat and

chicken skin.Saturated fatty acids are cholesterologenic, i.e.they increase blood cholesterol level.Aquatic animals like the fish, especially the marinefish, have good preponderance of polyunsaturated

fatty acids and their fat is actually OIL.


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OilsWhen polyunsaturated fatty acids predominate,then it is liquid at room temperature and istermed as OIL.Usually, triglycerides of plant sources are OILs.Examples are vegetable oils - mustard oil,soybean oil, sunflower oil, corn oil and othercooking oils.However, coconut and palm oil contain largeproportions of saturated and monounsaturated

fatty acids.


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CholesterolSome food items are rich in preformedcholesterol. Examples: egg yolk, liver,brain, chicken skin.

Forms of blood cholesterolHDL = Good cholesterolLDL = Bad cholesterol


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Fat provides the building materials for some bodyparts, such as brain, nerves and hormones.It also facilitates absorption, transport andstorage of fat-soluble vitamins A, D, E and K.Fat is therefore an essential nutrient. Like all othernutrients, fat is beneficial if consumed in the rightamount and if it is the right type.


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Since high blood cholesterol is a risk factor forcoronary heart disease, diet rich in preformedcholesterol and saturated fat is to taken withcaution after a certain age. It is, however, not aproblem for infants and young growingchildren.


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Vitamins Vitamins are food constituents vital for life.

They cannot be synthesized in the body andmust therefore be taken with food. They are,however, needed in minute amounts.

Vitamins help in the metabolism andutilization of the carbohydrate, protein and fatin the cells. They act as helpers (coenzymes)of enzymes involved in these metabolisms.

Vitamins thus help regulate body functionsand maintain health. They also protect the

body against infections.


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Vitamins are either water-soluble or fat-soluble.

Water-soluble vitamins are the B-complexvitamins and vitamin C.

B-complex vitamins are vitamin B1, B2, B6, B12,

niacin, folic acid, biotin, pantothenic acid. Fat soluble vitamins are vitamins A, D, E and K.


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Soluble vitamins, when taken in excess ofbody needs, are excreted in urine.

On the other hand, fat-soluble vitamins, whentaken in excess, are stored in the body

(particularly liver) for use at times when theintake of these vitamins is inadequate.

Most vitamins can be derived from liver,fruits, vegetables, legumes and grains.


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A few of the key roles and rich dietary sources

of some vitamins of public health importanceare listed in the table below.


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Function Rich sources

Thiamin(vitamin B1)

Helps release energy fromnutrients; supports normal

appetite and nerve functionCereal grains, pulses, yeasts;Green vegetables, fish, meat, fruit,

milkRiboflavin(vitamin B2)

Helps release energy fromnutrients; supports skin health;prevents deficiency manifestedby cracks and redness atcorners of mouth, inflammationof the tongue and dermatitis

Milk and its non-fat products;Green vegetables, meat, fish, egg

Niacin Helps release energy fromnutrients; supports skin,nervous and digestive systems

Liver, ground nuts, cereal bran orgerm

Pyridoxine(Vitamin B6)

Helps make red blood cells;helps in amino acid and fatty

acid metabolismWidely present in both plant andanimal foods

Folic acid Helps in the formation of DNAand new blood cells includingred blood cells; preventsanemia, some birth defects,heart disease

Dark-green leaves, liver, kidney


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Vitamin C Helps in the formation ofprotein, collagen, bone, teeth,cartilage, skin and scar tissue;facilitates the absorption of

iron from the gastrointestinaltract; involved in amino acidmetabolism; increasesresistance to infection

Fruits, vegetables and dark-green

leaves

Vitamin A Maintains normal vision, skinhealth, bone and tooth growth,reproduction and immunefunction, preventsxerophthalmia

Animal sources: Butter, eggs, milk,liver;Plant sources: Dark-green leafyvegetables, mangoes, papaya,tomato

Helps in the mineralization ofbones by enhancing absorptionof calcium

Fish liver oils, eggs, cheese, milkand butter; Sunlight inducessynthesis of vit. D in the body fromskin cholesterol.

Strong antioxidant; helpsprevent atherosclerosis;protects neuromuscularsystem; important for normalimmune function

Vegetable oils, germinated whole-grain cereals

Vitamin D

Vitamin E


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MineralsMinerals are inorganic chemical elementspresent throughout the body in varying amounts.Like the vitamins, they cannot be synthesized inthe body and must be taken with food.Minerals act as co-factors of enzymes formetabolism.Minerals form part of the structure of bodytissues, such as bones, teeth and nails, blood,nerves and muscles.


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Minerals are vital to physical and mentaldevelopment. They also help protect the bodyagainst infections.

Meat, fish, milk, cheese, green leafyvegetables and legumes provide most of theminerals needed by the body.

Some of the key roles of minerals are shown in the table


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Some of the key roles of minerals are shown in the tablebelow.

Mineral Function

Calcium Mineralization of bones and teeth; regulator of manyof the bodys biochemical processes; involved inblood clotting, muscle contraction and relaxation,nerve function, blood pressure and immune defenses

Phosphorous Mineralization of bones and teeth; part of every cell;used in energy transfer and maintenance of acid-base

balance

Sodium Maintains normal fluid and electrolyte balance,assists nerve impulse initiation and musclecontraction

Chloride Maintains normal fluid and electrolyte balanceChromium Works with insulin and is required for release of

energy from glucose

Copper Necessary for absorption and use of iron in theformation of hemoglobin


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Fluoride Involved in the formation of dental enamel andprevents dental caries; involved in the formationof teeth and skeleton and inhibits osteoporosis inold age

Iodine As part of the two thyroid hormones, iodineregulates growth, physical and mentaldevelopment and metabolic rate

Iron Essential in the formation of blood; involved inthe transport and storage of oxygen in the blood

and is a cofactor bound to several non-hemeenzymes required for the proper functioning ofcells

Sulfur Integral part of vitamins, biotin and thiamin, aswell as the hormone insulin

Zinc Essential for normal growth, development,reproduction and immunity

Magnesium Involved in bone formation and tissue energymetabolism

Di t Fib


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Dietary Fibre Dietary fibres are non-digestible, non-

absorbable components of food.

Fibres form the bulk of the stool and help inclearing the bowel and in preventingconstipation and colon cancer.

Fibres inhibit absorption of glucose andcholesterol from the GI tract, thus are helpfulin diabetes and heart disease.

Fruits, vegetables, pulses and whole cerealsare sources of dietary fibre.

Our daily diet should contain some fibre for

good health and well being.


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Non-nutrient components of health significance Some plant foods show additional health benefits

beyond basic nutrition. These foods are calledFunctional Foods.

These ingredients protect our body from variousdiseases like diabetes, hypertension, and someforms of cancer.

Bright examples of functional foods are tomatoes,mushroom, apple and guava, garlic, onion, ginger,cloves and other spices, cabbage, cauliflower,broccoli, blackberry, and tea.

The above functional foods should be a part ofour daily dietary.


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Classification of Functional Food*

cabbage, cauliflowerBrassica species

coloured vegetables

Garlic, onions

Example

fruits, vegetables, coffee, tea and alcoholicbeverages.

Products of thephenylpropanoidpathway

vascular plantsProducts of theisoprenoid pathway

AlliumOrganosulphur

compounds

SourcePhytoprotectants


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Phytoprotectants in vegetables

Allyl sulphides

It is, however, not certain if cookedgarlicand onions work as well as raw.**

RawGarlic & Onions

Alliin & allicin

Worksagainst

Helicobacterpylori

Stomachulcers

Works as*

Anticancer

Hypocholesterolemic Hypotriglyceride


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Works asCarotenoids,

chiefly lycopene

Tomatoes

Prostatecancer& othercancers

Anticancer Worksagainst

Helpfulagainst

Heart disease



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Soluble fibre pectin

Ladys finger,Puisak

Has Hypoglycaemiceffects

Reduces

Bloodcholesterol

Mucinousvegetable


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Phytoprotectants in tea

Catechins,theaflavins

TEA

HasAntihypertensive effect byinhibiting angiotensin I -converting enzyme (ACE)


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Phytoprotectants in spices

Gingerol,curcumin

Ginger, cumin

Flatulenc

e

Carminativeaction

Relieves

Has

Anti-inflammatoryaction

Has


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Phytoprotectants in whole cereals

Brown rice, wholewheat

Rich in fiber

Neutralize

Whole grains

terpenoids, phytic acid,ellagic acid,

phytoestrogens(lignans)

Reduce risk

of

Heart disease and cancerrisk, particularly breast

cancer.

Reduce riskof

Colon cancer

Cancer- causingagents in the

intestine

FUNCTIONAL FOODS OF CURRENT INTEREST IN


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FUNCTIONAL FOODS OF CURRENT INTEREST IN

BANGLADESH: Mushrooms

Eritadenine & antadenine

Mushrooms(Oyster varieties) Hypocholesterolemic

effect

Conversion of cholesterol intobiles

Helps

Lovastatin

hydroxymethyl glutaryl CoAreductase

(HMGCoA reductase)Lowers blood cholesterol

level

Synthesis of

cholesterol


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4a macronutrients and micronutrients_ non nutrient food ingredie

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