Special Issues in Nutrition

I

Assessment Statements Obj.

A2.1 Distinguish between the components of human milk and artificial milk for bottlefeeding babies. 2

A2.2 Discuss the benefits of breastfeeding. 3

A2.3 Outline the causes and symptoms of type II diabetes. 2

A2.4 Explain the dietary advice that should be given to a patient who has developed type II diabetes. 3

A2.5 Discuss the ethical issues concerning the eating of animal products, including honey, eggs, milk and meat. 3

A2.6 Evaluate the benefits of reducing dietary cholesterol in lowering the risk of coronary heart disease (CHD). 3

A2.7 Discuss the concept of food miles and the reasons for consumers choosing foods to minimize food miles. 3

Assessment statements from: Online IB Biology Subject GuideCommand terms: http://i-biology.net/ibdpbio/command-terms/

Breast-milk Formula

Colostrum Present in first feeds. Stimulates newborn digestion. Not present

Antibodies Present in colostrum in high doses, and subsequent milk. Not present

Protein Lower, but more easily digested and absorbed. Human.

Higher, but harder to digest and absorb. Bovine sources.

Carbohydrates Higher in lactose, linked to brain development.

Lower in lactose. May come from glucose.

Fatty acids Human fatty acids. Palm oil or alternatives .

Vitamins and minerals May be lower, but easier to absorb. Higher, but harder to absorb.

Breast is BestHow does human milk compare to formula milk?

Breast is BestWhat are the benefits of breastfeeding?

Benefit Effect

Immunity Colostrum and early breastmilk contain high concentrations of antibodies, protecting the infant from infections.

Digestive function Colostrum stimulates digestive tract function and eases defecation. Easier to digest than formula milk.

Cost Breastmilk is free and readily available as long as the mother remains healthy

Bonding Aids in mother-child bonding and communication

Nutrition More complete than formula and changes in composition to match the needs of the infant

Mother’s health Aids in weight-loss, reduces risk of breast cancer, type II diabetes and post-partum depression.

Type II DiabetesWhat are the symptoms and causes?

“Using econometric models of repeated cross-sectional data on diabetes and nutritional components of food from 175 countries, we found that every 150 kcal/person/day increase in sugar availability (about one can of soda/day) was associated with increased diabetes prevalence by 1.1% (p <0.001).”

What is the relationship between obesity and type II diabetes (insulin resistance)?

What is the effect of increasing access to sugar on the prevalence of diabetes?

Type II DiabetesWhat are the symptoms and causes?

Causes• Prolonged excessive intake of high-energy

foods, particularly sugars and carbohydrates• Insulin resistance develops as a result as insulin

receptors on the liver become less sensitive• Strong link to obesity (excess energy is stored

as fat)• Genetic factors (some are more susceptible to

developing type II diabetes)

Symptoms• Glucose in the urine (too much glucose in the

blood, not all can be re-uptaken by the kidney so some remains in urine)

• Dehydration, excessive urination• Damaged blood vessels• Weight loss as fat storage is affected• Sleep loss, tiredness• Blurred vision/ potential loss of sight

(retinopathy)

Type II DiabetesWhat dietary* advice would a patient receive and why?

Advice Scientific Reason

Eat low GI foods. Some foods release energy more slowly - they have a lower glycemic index (GI). Eating these reduces ‘spikes’ in blood sugar.

Cut out sugars & refined carbohydrates

These are high GI foods – they are broken down into sugars and absorbed quickly, causing blood sugar to rise quickly. They include sugary snacks, white bread and pasta.

Eat high fibre foods High fibre makes one feel without providing too much energy. High fibre diets can also help reduce the effects of diabetes.

Small, regular meals Smaller releases of energy more frequently result in less dramatic blood sugar changes than large, infrequent meals.

Choose ‘diabetic alternatives’

Some packaged foods may be labeled to show that they have reduced sugars or carbohydrates, suitable for diabetics.

Read the food labels Learn how to read and interpret food labels to avoid eating unsuitable foods.

*Yup, getting more exercise would be useful too (but that’s not dietary).

Eating AnimalsWhat are the ethical issues associated with animal products?

Eating AnimalsWhat are the ethical issues associated with animal products?

Food Product Advantages Ethical Concerns

Meat Source of proteins, some vitamins and minerals.

• Animal welfare issues in intensively-farmed cattle, poultry. Pain and suffering in slaughter.

• Growth of antibiotic-resistant bacteria and new strains of viruses as a result of overuse of medication. Use of growth hormones may affect human health, such as earlier onset of puberty.

• Huge demand for land and water to grow crops to feed animals is no longer sustainable and results in clearing of rainforests and habitat destruction. Methane and other emissions from farming livestock contribute to global warming.

Fish Source of proteins and helpful fatty acids.

• Many fish species are endangered due to overfishing.• Concerns of bio-magnification of toxins in the food chain and risks to human health.

Milk Source of energy, protein, calcium

• Animal welfare issues in intensively-farmed cattle, poultry. • Growth of antibiotic-resistant bacteria and new strains of viruses as a result of

overuse of medication. • Huge demand for land and water to grow crops to feed animals is no longer

sustainable and results in clearing of rainforests and habitat destruction. Methane and other emissions from farming livestock contribute to global warming.

EggsSource of protein and fats, a ‘meat’ alternative in some

cultures

• Cholesterol health risks associated with too much egg yolk consumption. • Battery-farmed chickens fed hormones, in cramped conditions and can be treated

inhumanely. Living spaces can be dirty and encourage spread of illness. • Male chicks are routinely culled as they cannot produce eggs.

HoneyHoney is a natural sweetener.

Bees pollinate many flower species.

• Farmed bees compete with local insect and bee populations for nectar. Artificial selection of bees will result in a genetic shift in bee populations.

Reducing CholesterolWhat are the health benefits and where is the evidence?

Cholesterol is needed in small amounts in the body to produce hormones and plasma membranes. In excess it is thought to contribute to atherosclerosis by forming deposits in the arteries. Rupture of plaques can cause clots, or CHD. However, this is a paradigm that is being challenged and it highlight the correlation-cause argument.

In a review of studies, it has been suggested that the link between dietary cholesterol intake and CHD is not logical, and that the more likely cause of CHD is a diet high in saturated fats. Diets high in saturated fats tend to be high in cholesterol, so there is a correlation without necessarily causation.

With moderate cholesterol intake, the body is able to remove excess with no harmful effect – dietary cholesterol is not necessarily converted into plasma cholesterol. Plasma cholesterol can be HDL (not harmful), or LDL (plaque-forming).

Extreme intakes may lead to a greater buildup of LDL in atherosclerosis. Although there is a small risk of cholesterol leading to CHD, the risks of smoking, inactivity and heredity are much stronger and more closely related to CHD.

Although a cholesterol-controlled diet may slow or reduce the risk of atherosclerosis, it must be combined with a healthy diet and lifestyle if it is to have a significant effect on reducing the risk of CHD.

Food MilesWhat is the footprint of your food?

Food miles are a measure of the distance a food product travels from ’plough to plate’. It is an indicator of the environmental impact of the foods we eat, as this travel involves costs in fuel, emissions, packaging and time: the further a product travels, the less sustainable it is. Some imported foods cost more in energy per gram for their transport than they provide for the consumer.

Some consumers prefer to choose locally grown or farmed food products to reduce the costs, use of packaging and preservatives, use of oil/fuel and emissions. They may also hope to encourage outlets to use local providers of produce rather than imported goods.