1. Human nutrition
and health
A3. Special issues in human
nutrition
1

2. 2 November 1, 2011
Breast feeding babies
 Advantages of breast feeding:
 Promotes bonding between mother and baby
 Acts as a natural birth-control method, reducing
the chance of conception while the mother is
lactating
 Helps mother loose weight after pregnancy,
helps prevent breast cancer and post partum
depression
 Avoids the allergies to proteins in cow’s milk that
can develop when babies receive formula.
 Colostrum and early breast milk contain high
concentrations of antibodies, helping protect
baby from infections
 Breast milk is free and available as long as
mother remains healthy

3. 3 November 1, 2011
Human vs. Artificial milk
Composition Human milk Artificial milk
Carbohydrate lactose Lactose or glucose
polymers
Protein source 65% whey proteins, 18% bovine whey and
35% casein 82% bovine casein, or
soya proteins
Fatty acids Human butter fat Palm, coconut, soy or
safflower oils
antibodies Present mostly in the No antibodies present
first milk (colostrum)
Vitamins ans minerals May be lower, but Higher, but harder to
easier to absorb absorb (bio-
availability)

4. 4 November 1, 2011
Type II diabetes
 Several forms of diabetes. Diabetes
mellitus is the most common.
 Type I diabetes: auto-immune destruction
of insulin-secretin cells in the pancreas
(not enough cells that make insulin)
 Type II diabetes: decreased
responsiveness of body cells to insulin (not
enough insulin receptors on target cells)

5. 5 November 1, 2011
Type II diabetes
 After many years, diabetes can lead to
serious problems with your eyes, kidneys,
nerves, and gums and teeth. But the most
serious problem caused by diabetes is heart
disease. When you have diabetes, you are
more than twice as likely as people without
diabetes to have heart disease or a stroke.
 Other related health problems related to the
cardiovascular system:
 Atherosclerosis, hypertension, CHD

6. 6 November 1, 2011
Type II diabetes
 Incidenceof type II diabetes is increasing
in many countries that show risk factors:
 Diets rich in fat and low in fiber
 Obesity due to overeating and lack of
exercise (the receptors in the liver ‘wear
out’ or become resistant to insulin)
 Genetic factors which affect fat
metabolism.

7. 7 November 1, 2011
Regulation of sugar levels in
the blood a) Low glucose concentration is
detected by the pancreas.
b) Alpha cells in the pancreatic
islets secret glucagon.
c)Glucagon flows through the
blood to receptors on liver cells.
d)Liver responds by adding
glucose to blood stream.
h) High blood glucose levels
stimulate the beta pancreatic cells
a) Beta pancreatic cells secrete
insulin.
f)Insulin flows through the blood to
the receptors on liver cells.
g)Insulin stimulates the liver to
remove blood glucose and store
this as glycogen (insoluble)

8. 8 November 1, 2011
Type II diabetes
 The main symptoms are:
 being very thirsty and/or urinating often
 feeling very hungry or tired
 losing weight without trying
 having sores (injuries) that heal slowly
 having dry, itchy skin
 losing the feeling in your feet or having tingling
in your feet
 having blurry eyesight
 elevated levels of blood glucose or glucose in
the urine (detected in lab tests)

9. 9 November 1, 2011
Type II diabetes
 It
can be controlled through careful diet
and healthy lifestyle

10. 10 November 1, 2011
Ethical issues in human diets
 Discuss the ethical issues concerning the of
eating of animal food products, including
honey, eggs, milk and meat.
 Beliefs:
 It is wrong to eat food if its production involves
animal suffering.
 Vegetarians do not eat meat because an animal
must be slaughtered, however they are willing to
drink milk and eat eggs because animals do not
need to die to produce them.
 Vegans do not eat meat, eggs nor drink milk or
even honey.

11. 11 November 1, 2011
Ethical issues in human diets
 Meat
 Advantages: source of proteins, some
vitamins and minerals.
 Ethical concerns:
 animal welfare, pain and suffering
 Use of growth hormones affects humans, growth
of antibiotic-resistant strains of bacteria
 Huge demand for land and water for feeding
animals. Methane production contributes to
global warming.

12. 12 November 1, 2011
Ethical issues in human diets
 Fish:
 Advantages: source of proteins and
healthy fatty acids
 Concerns:
 Overfishing
 Biomagnification of pollutants and toxins
can be harmful to humans (mercury)

13. 13 November 1, 2011
Ethical issues in human diets
 Milk
 Advantages: source of proteins, calcium and
energy
 Concerns:
 Animal welfare. Cows need to give birth to
calves to produce milk. Few are needed for
replacement, most are grown for meat or
sacrificed soon after birth.
 Increase in antibiotic-resistant bacteria
 Huge demand for water and soil (deforestation)

14. 14 November 1, 2011
Ethical issues in human diets
 Eggs
 Advantages: source of proteins and fat
 Concerns:
 Male chicks are often sacrificed since they
cannot produce eggs.
 Animal welfare and living conditions can
propagate illnesses
 High egg yolk consumption associated to
high cholesterol levels and poor health.

15. 15 November 1, 2011
Ethical issues in human diets
 Honey
 Advantages: natural sweetener, provides
energy. Bees pollinate many flowers.
 Concerns:
 Farmed bees compete with wild local
insects and bees for nectar.
 Artificial selection of bees will result in
genetic shift in bee populations.

16. 16 November 1, 2011
Cholesterol
 Itis a normal component of plasma
membranes in human dells.
 LDL – low density lipoprotein
 HDL – high density lipoprotein
 Positive correlation between high levels of
cholesterol in blood plasma and an
increased risk of coronary heart disease
(CHD). However, this is being challenged.

17. 17 November 1, 2011
Cholesterol
 Only LDL is implicated in CHD, but studies focus on
total blood cholesterol levels.
 Reducing dietary intake of cholesterol often has a
very small effect on blood cholesterol levels.
 The liver can synthesize cholesterol
 Genetic factors: some families have high
cholesterol levels even with a low dietary intake.
 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, that also tend to be high in
cholesterol, so there is a correlation without
necessarily causation.

18. 18 November 1, 2011
Food miles
 Where does your food come from?
 How distant is the place of origin of the
food you eat?
 How much energy has been spent to
transport your food?
 How much fuel has been burned, and
therefore how much CO2 has been
released into the atmosphere?

19. 19 November 1, 2011
Food miles
 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
 Environmentalists campaign for less
transport of food and more consumption
of locally produced food.

20. 20 November 1, 2011
Food miles
 Advantages:
 Local foods are cheaper and fresher
 Less wrapping and packaging
 Boost of local economy and farmers
 Less imported goods
Disadvantages:
Seasonal availability of food
Reduced food options

21. 21 November 1, 2011
Food miles
 Can consumers affect the environment by the
choices they make in buying food?
 Should we consider ethical issues when we buy
food, or should we leave it up to governments?
 Is it right that buying locally produced food is a
form of protectionism, which can harm farmers in
the developing world?
 Evaluate the claim that internet shopping and
home delivery of food reduce the use of energy in
food transport
 Referring to the precautionary principle, should we
wait until more research has been done before
changing our pattern of consumption?