Human Health and Nutrition

Nutrients

• Nutrients- a chemical substance found in foods and used in the human body.– Essential nutrients- must obtain from food, body

cannot make them.• Essential amino acids (9)• Essential fatty acids• Minerals• Most vitamins• Water

Protein Deficiency

• Leads to insufficient production of blood plasma proteins– Retention of fluids in small intestine

Kwashiorkor

• Results from malnutrition– Not enough protein– Mother has second child and feeds him first, older

child is left with not enough milk.– Cure: Eat more protein!

Phenylketonuria (PKU)

• Do not have the enzyme that converts phenylalanine to tyrosine– Buildup will affect brain development

• Follow a special diet low in protein and phenylalanine

Fatty Acids

• Carboxyl at one end• Methyl at the other end• Chain of hydrocarbons in between

Fatty Acids

• Saturated- the carbons are saturated with hydrogens (no double bonds)

• Monounsaturated- One double bond (one kink)• Polyunsaturated- at least 2 double bonds (twists)

Hydrogenation

• Hydrogenated- double bonds are eliminated by adding hydrogen

• Straightens out the chain– Cis fatty acids- Naturally curved – Trans fatty acids- hydrogenated straightened ones

• Omega-3 (cis)- the first double bond is found on the 3rd carbon counting backwards from the carboxyl (omega) end.

Good or Bad?

• Straight fats are bad- they will be more likely to stick to the walls of the arteries

• Curved fats are good- they will be more likely to be swept up by the blood

• Saturated/trans contribute to plaque buildup.– Heart=heart attack– Brain=stroke

Vitamins and Minerals

• Minerals- – Inorganic– Do not contain carbon– Not synthesized by living organisms

• Vitamins– Organic– Always contain carbon– Synthesized in plants and animals

Vitamins and Minerals

• Minerals- Na+, Ca++, Fe++ (Single elements in ion form)

• Vitamins- A (C20H30O) C (C6H8O6) (compounds)• Both needed in very small quantities, both

prevent deficiency diseases.

Vitamin C (30-60mg)• Too little= scurvy

– Retention of fluid– Loss of teeth– Bleeding into joints– Anemia– Lethargy

• Too much= rebound malnutrition– Body gets used to getting rid of extra and keeps that level high no

matter how much you take in.• Comment: Used animal studies and human studies

(conscientious objectors in WWII) to determine accurate level

Vitamin D

• Too little= rickets– Bones don’t form properly

• How to get vitamin D– Sun (15 minutes, twice a week)– Foods rich in D• Fish, eggs, liver, milk is fortified with it

– Vitamin supplements

Artificial supplements

• Iodine- people that eat enough seafood are fine. (There wasn’t enough in certain places)

• Insufficient iodine – leads to goiters• Swelling of the thyroid gland

– Babies can get cretinism: stunted growth and mental problems.

• Our solution?

Artificial supplements

• Iodized salt!• 1924- 40% of people around Great Lakes had

goiters• Now- practically nonexistent

Fiber (fibre in IB)

• Cellulose material in plants• Helps human digestion by providing bulk• Can reduce risk of diabetes and cardiovascular

disease• Help manage body mass• Eat 5-8 servings of fruit and vegetables a day

Energy in diets

• Carbohydrates= 1760 kJ/100g• Protein= 1720 kJ/100g• Lipids= 4000 kJ/100gComments:• Main energy storing bonds are between

carbons and hydrogens• Lipids have more C-H bonds than the others.

Different energy for different ethnicities

• Rice= China, Japan, India, Indonesia, Bangladesh, Vietnam, and Thailand

• Wheat= Russia, Australia, Canada, Iran• Cassava (yuca)= Caribbean• Maize (Corn)= Mexico• Fish and Meat= Coastal areas, Islands, Inuit

populations, USA

Everything in Moderation

• Excess Carbs= Excess sugars will be stored as glycogen or fat

Everything in Moderation

• Excess Fat= will be stored but since it contains so much more energy, more will be stored sooner than carbs

Everything in Moderation

• Excess protein= (>50g) Can’t store excess, liver and kidneys eliminate it= overworking your kidneys and liver– In the process, kidneys use calcium, they will steal

from bones to get enough.

Appetite control

• A combination of feedback loops from nervous system, digestive system, and endocrine system.

• Hypothalamus: appetite control center.– Stomach fills with food and expands, stimulating a

nerve that signals the hypothalamus to stop eating.

Appetite control

• Leptin: a hormone secreted by fat cells that tells the brain that you have enough energy stored.– Advertising and compulsive eating can override

this.

Body Mass Index

• BMI= (mass in kg)/ (height in m)2

• Should be in high teens to mid 20s. • Underweight= below 18.5• Normal weight=18.5-24.9• Overweight= 25.0-29.9• Obese= 30.0 and above

BMI problem

• Does not say how mass is distributed – Muscles– Heavy bones

Why are so many people obese?

• Change in type and quantities of food• Change in amount of physical activity• Availability of food has increased• Need for physical activity has decreased

What can you do?

• Eat more fruits and vegetable and less overall• Take the stairs instead of the lift• Increase physical activity

Anorexia nervosa

• Intense fear of gaining weight– Refuse food– Regurgitate food– Exercise excessively

Consequences of Anorexia

• Endocrine system malfunctions

• No menstrual cycle• Loss of head hair• Dehydration• Fainting • Anemia• Low blood pressure• Kidney failure

• Increased infection and illness

• Osteoporosis• Psychiatric issues• Cannot get pregnant• Higher chance of

miscarriage• Starve to death– 6-20% of cases

Treatment

• Need a Healthy self image (influenced by):– Cultural pressures– Traumatic experiences– Physiological causes from genetics or brain

chemistry

Breast milk vs. formula

Breast milk• Enzymes amylase and lipase• White blood cells• Antibodies• Hormones• More Lactose for more

energy• More cholesterol

Breast milk vs. formula

For Breast feeding Against Breast feeding• Milk is species specific• High % of whey and low casein

proteins (easier digestion)• Proteins induce sleep• Nutrients are more easily

absorbed• No allergies• Bonding• Helps mother lose baby weight• Better immune system• Less expensive

• Can be painful to mother• Pathogens can be spread

(HIV and other viruses)• Not accepted by some

cultures in public• Hard to maintain a career• Father feels left out

Type II diabetes

• Body develops an insensitivity to insulin over many years– Obese – Genetic factors

• Native Australians• Native Americans• Maoris

• Leads to high blood pressure, eye damage, kidney malfunctions, nerve disease, stroke, and heart attack.

Type II diabetes

• AKA: Adult onset, non-insulin-dependent diabetes

• Symptoms-– More thirsty than normal– Urinating more often– Feeling tired– More infections

Vegetarianism? (From IB)

Yes No• Killing sentient beings is

wrong• Raising animals for slaughter

is wrong• Livestock production is

wasteful and misuses valuable resources

• Cruel treatment of livestock• Fishing pollutes oceans and

disrupts ecosystems

• Cows, sheep, pigs, chickens would not exist

• Thousands of jobs would be lost

• Meat and fish can be grown in free-range style

• Certain nutrients are not available in vegetarian diet

Food Miles

• How far the food has traveled to get to the market

• Farmers sell their food to supermarket distributors to process and ship, sometimes back to where it started

• The further the distance, the more fossil fuels used

Food miles

• Have access to a wide variety and can support international farmers (coffee, etc.)

What you can do:• Make informed decisions• Shop at farmer’s market, benefits local

farmers immediately• Best Choice, Always Save brands are packaged

in local areas