chapter 6 lecture outline

CHAPTER

6Vitamins: Micronutrients with Macro Powers

Chapter 6 Outline

I. What Are Vitamins?

A. Vitamins are carbon compounds that are essential in regulating the body’s processes.

1. Fat-soluble vitamins are stored in the body.

2. Water-soluble vitamins should be consumed daily or weekly.

3. Vitamins are vulnerable!

a. Watch the water: soak and cook with as little water as needed.b. Lower the heat: avoid high temperatures for long periods during cooking.c. Limit the light: some vitamins are destroyed by light and should be stored in opaque

containers.

d. Avoid air: vitamins A, C, E, K, and B are destroyed by prolonged exposure to air.

e. Don’t disturb the pH of the cooking medium: alkaline water destroys a number of vitamins.

II. Tissue Guardians: Vitamins A, D, and K.

A. Vitamin A protects our sight.

1. How else do we use vitamin A?a. It potentiates cell differentiation: the process by which immature cells develop into

specialized cells.

b. Vitamin A helps break down old bone tissue.

c. It is involved with sperm production in men and fertilization in women.

d. It is associated with lower risks of some forms of cancer and heart disease.

2. What is the role of beta-carotene?a. It is a water-soluble provitamin, an inactive form of vitamins found naturally in the body.

b. It defends against damage to our cell membranes.

c. It enhances our immune system.

d. It protects our skin from the damage caused by the sun’s rays.

e. It helps prevent age-related vision impairment.

3. How much vitamin A should we consume?

a. Vitamin A can be obtained from some animal foods such as beef liver, chicken liver, eggs, and dairy products.

b. Vitamin A is also available from foods high in beta-carotene and other carotenoids, which the body can convert to vitamin A.

Copyright © 2016 Pearson Education, Inc. 38

c. Vitamin A is highly toxic.

d. Consumption of vitamin A during pregnancy can result in birth defects.

e. Toxicity symptoms are loss of appetite, blurred vision, hair loss, abdominal pain, nausea, diarrhea, and even death.

f. Night blindness is the condition that results from vitamin A deficiency.

g. Other deficiency symptoms include irreversible blindness, impaired immunity, reproductive system disorders, and growth failure.

B. Vitamin D guards our bones. It is a hormone as well as a nutrient.

1. How much vitamin D should we consume?

a. Vitamin D regulates blood calcium levels and maintains bone health.

b. Vitamin D requirements are based on the assumption that an individual does not get adequate sunlight.

c. Most foods naturally contain very little vitamin D.

d. Toxicity of vitamin D causes the bones to leach calcium into the bloodstream.

2. What happens if we don’t get enough vitamin D?

a. The primary symptom is loss of bone mass.

b. A vitamin D deficiency in children is rickets.

c. In adults, a deficiency is ostemalacia, and it can contribute to osteoporosis.

d. A vitamin D deficiency may also be associated with other diseases.

C. Vitamin K protects against blood loss.

1. Vitamin K is a fat-soluble vitamin that acts as a coenzyme and is essential for blood clotting.

2. A coenzyme is a molecule that combines with an enzyme to activate it and help it do its job.

3. Healthful bacteria in our intestines produce vitamin K.

4. Good food sources of vitamin K include green leafy vegetables and vegetable oils, such as soybean and canola.

5. There appear to be no side effects associated with consuming large amounts of vitamin K.

6. Those who suffer from fat malabsorption can develop a deficiency of vitamin K.

III. The Antioxidants: Vitamins E and C

A. What are antioxidants and how does our body use them?

1. Antioxidants are compounds that protect our cells from the damage caused by oxidation.

2. Oxidation sometimes results in the formation of free radicals.

3. Free radicals can destabilize other molecules and damage our cells.

4. Nutrients that act as antioxidants include vitamins C and E, carotenoids, and selenium.

B. Vitamin E maintains healthy cells.

1. Vitamin E is critical for normal development of nerves and muscles, enhances im-mune function, and improves absorption of vitamin A.

2. Vitamin E is widespread in the foods we eat.

a. Sources include vegetable oils, nuts, seeds, and some vegetables.

b. Vitamin E is destroyed by exposure to oxygen, metals, ultraviolet light, and heat.

39 INSTRUCTOR MANUAL FOR NUTRITION FOR LIFE, 4/e Copyright © 2016 Pearson Education, Inc.

c. Vitamin E toxicity is uncommon.

d. Vitamin E deficiency is rare, but it can lead to a rupturing of red blood cells leading to anemia.

C. Vitamin C protects cells and tissues.

1. How else do we use vitamin C?

a. Vitamin C is an antioxidant and regenerates vitamin E after it has been oxidized.

b. Vitamin C assists in collagen synthesis and enhances the immune response.

c. Vitamin C assists in the synthesis of DNA, neurotransmitters, and various hormones.

d. Vitamin C enhances iron absorption.

2. How much vitamin C should we consume?

a. Fruits and vegetables are the best sources of vitamin C.

b. Heat and oxygen destroy vitamin C.

c. We excrete excess vitamin C easily because it is water soluble.

d. Side effects of megadoses may include nausea, diarrhea, nosebleeds, kidney stones, and abdominal cramps.

IV. The Energy Generators: B-Vitamins

A. Our bodies require vitamins and minerals to produce energy; but vitamins and minerals contain no Calories.

1. The B-vitamins are particularly important in assisting with energy metabolism.

B. How does our body use B-Vitamins to produce energy?

1. The primary role of the B-vitamins is to act as coenzymes.

C. Thiamin (Vitamin B1) helps metabolize glucose.

1. Thiamin was the first B-vitamin discovered and is therefore named vitamin B1.

a. Thiamin is part of a coenzyme that plays a critical role in the breakdown of glucose for energy.

b. Thiamin aids in the metabolism of protein, producing DNA, and the synthesis of neurotransmitters.

c. Good food sources include enriched cereals and grains, whole-grain products, and pork products.

d. Thiamin-deficiency disease is called beriberi.

e. There are no known adverse effects from consuming excess thiamin.

2. Riboflavin (Vitamin B2) helps break down carbohydrates and fats.

a. Riboflavin is an important component of coenzymes involved in the breakdown of fat and carbohydrates.

b. Riboflavin is part of an antioxidant enzyme.

c. Good food sources include milk, yogurt, enriched bread and grain products, and organ meats.

d. There are no known adverse effects from consuming excess riboflavin.

e. Symptoms of riboflavin deficiency (ariboflavinosis) include sore throat, swelling of mucous membranes in the mouth and throat, dry and scaly lips, and purple tongue.

3. Niacin helps produce energy and build and repair DNA.

a. Niacin plays a role in cell differentiation.Copyright © 2016 Pearson Education, Inc. CHAPTER 6 Vitamins: Micronutrients with Macro Powers 40

b. Good food sources include meat, fish, poultry, and enriched bread and grain products.

c. Niacin can cause toxicity symptoms, including flushing.

d. Pellagra results from niacin deficiency.

4. Vitamin B6 (Pyridoxine) helps manufacture nonessential amino acids.

a. Vitamin B6 is part of a coenzyme for more than 100 enzymes involved in protein metabolism.

b. Good food sources include enriched cereals, meat, fish, poultry, white potatoes, organ meats, and fortified soy-based meat substitutes.

c. Vitamin B6 supplements have been used to treat conditions such as premenstrual syndrome and carpal tunnel syndrome.

d. Vitamin B6 supplements may result in nerve damage and skin lesions.

e. Symptoms of vitamin B6 deficiency include anemia, nervous system symptoms, dermatitis, and elevated levels of the amino acid homocysteine in the blood.

5. Folate is critical during the earliest weeks of pregnancy.

a. Folate is involved in DNA synthesis and amino acid metabolism.

i. Folate is a critical nutrient during the first few weeks of pregnancy.

b. Folate works with vitamin B12 and B6 in homocysteine metabolism.

c. Good food sources include fortified cereals and bread products, green leafy vegetables, lentils, asparagus, and oatmeal.

d. Excess folate intake can mask B12 deficiency.

e. Folate deficiency can cause macrocytic anemia.

f. Folate deficiency in pregnant women can cause neural tube defects.

6. Vitamin B12 (Colbalamin) maintains healthy nerves and blood.

a. Vitamin B12 is part of coenzymes with several functions.

i. Vitamin B12 is necessary for healthy nervous system function.

ii. Vitamin B12 works with folate to break down homocysteine.

b. The only sources of vitamin B12 are dairy products, meats, and poultry.

c. Atrophic gastritis decreases vitamin B12 absorption.

d. Vitamin B12 deficiency causes pernicious anemia.

e. There are no known adverse effects from consuming excess vitamin B12.

7. Pantothenic acid and biotin help metabolize macronutrients.

a. Pantothenic acid assists with metabolism of fatty acids.

b. Food sources include chicken, beef, egg yolk, potatoes, oat cereals, tomato products, whole grains, and organ meats.

c. There are no known adverse effects from consuming excess amounts of pantothenic acid.

d. Deficiencies of pantothenic acid are rare.

e. Biotin is involved in carbohydrate, fat, and protein metabolism.

f. Biotin appears to be widespread in foods.

g. There are no known adverse effects from consuming excess biotin.

8. Choline is a vitamin-like substance found in foods.

a. Choline accelerates the synthesis and release of acetylcholine.


b. Choline plays an important role in the transport and metabolism of fat and cholesterol.

c. Choline assists in homocysteine metabolism.

d. Inadequate choline intake can lead to liver damage.

V. What About Supplements?

A. Dietary supplements are not strictly regulated.

1. Supplements do not need approval from the FDA before they are marketed.

2. The FDA does not test the product for safety, not does it require evidence of safety, purity, quality or composition from the manufacturer.

3. There are no rules limiting the serving size or amount of nutrient in a product.

B. Who might benefit from taking micronutrient supplements?

1. A single dose of vitamin K for newborns at birth.

2. Vitamin D supplements for breast-fed infants from birth to age 6 months and iron- fortified cereal for breast-fed infants 6 months of age and older.

3. Fluoride supplements for children not drinking fluoridated water.

4. Multivitamin/multimineral supplements for people on prolonged energy-restricted diets and for people with HIV/AIDS or other wasting diseases.

5. Calcium and vitamin D supplements for people at risk for low bone mass.

6. Vitamin B12 supplements for elderly people and vegans.

C. When can taking a vitamin or mineral supplement be harmful?

1. Providing fluoride supplements to children who already drink fluoridated water.

2. Taking supplements in the belief that they will cure a disease such as cancer, diabetes, or heart disease.

3. Taking supplements without checking with your healthcare provider to determine their reaction with medications you are taking.

4. Taking beta-carotene supplements if you are a smoker. Evidence suggests that beta-carotene supplementation may increase the risk for cancer in smokers.

5. Taking vitamins and minerals in an attempt to improve physical appearance, athletic performance, or energy level. There is no evidence that vitamin and mineral supple-ments enhance appearance, athletic performance, or energy level in healthy adults who consume a varied diet with adequate energy.

6. Taking supplements in excess of the tolerable upper limit (UL), unless your healthcare provider prescribes them for a diagnosed medical condition.

VI. Do Antioxidants Protect Against Cancer?

A. Cancer develops in three stages.

1. Initiation: the initiation of cancer occurs when a cell’s DNA is mutated.

2. Promotion: during this phase, the cell repeatedly divides.

3. Progression: during this phase the cancerous cells grow their own blood vessels, which supply them with blood and nutrients.

B. A diet high in antioxidants may help prevent cancer and other diseases.

1. Antioxidants enhance the immune system.

2. Antioxidants inhibit the growth of cancer cells and tumors.

3. Antioxidants prevent oxidative damage to the cells’ DNA.

Copyright © 2016 Pearson Education, Inc. CHAPTER 6 Vitamins: Micronutrients with Macro Powers 42

4. Antioxidants reduce inflammation in blood vessel walls, protecting against possible stroke.

C. Other factors may influence cancer risk.

1. Increasing consumption of fiber and phytochemicals has been proposed to decrease cancer risk.

2. Eat a variety of colorful fruits, vegetables, and whole grains daily, because these foods are rich in antioxidant nutrients and phytochemicals.

3. Limit your consumption of saturated and trans fats. Some studies suggest that diets high in saturated fat can increase our risk for some cancers.

4. Limit your consumption of red meats, processed meats, meats high in fat, and cured meats such as sausage, ham, bacon, and many lunch meats.

5. If you eat meat, avoid cooking methods that require high temperatures, such as broil-ing, frying, and barbecuing. High-temperature cooking methods prompt the develop-ment of carcinogens called heterocyclic amines.

6. Maintain a healthful weight. Obesity appears to increase the risk for certain cancers, possibly because of hormonal changes that occur in people with excess body fat.

7. If you drink alcohol, limit your consumption. Alcohol is a carcinogen.

8. If you smoke cigarettes or cigars or use smokeless tobacco, stop.

9. Limit your sun exposure and avoid sunburn. Skin cancer is the most common form of cancer in the United States.

10. Limit your exposure to environmental carcinogens.

11. Adopt a physically active lifestyle.

12. Follow cancer screening recommendations.
