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Nutrition Essentials: A Personal Approach
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UNIT 8
VITAMINS: NUTRIENTS THAT MULTITASK
OVERVIEW
Unit 8 begins with a general discussion of vitamins, including their classification as fat-soluble or watersoluble, major functions in the body, and how to get the most nutrition from foods. All of the vitamins
are summarized in table format. Of the 14 vitamins, 10 are covered in detail, with information about
each vitamin’s functions, requirements, dietary sources, and dietary adequacy. Unit 8 covers the biology
of cancer, risk factors, with special emphasis on dietary risk factors, and suggestions for cancer
prevention. Overall, dietary sources of nutrients, particularly a diet rich in fruits and vegetables, are
recommended to achieve and maintain optimal health.
LEARNING OUTCOMES
Module 8.1
1. Define all of the key terms in this module.
2. Describe the basic features that distinguish a vitamin from other naturally occurring substances
in foods.
3. Classify vitamins according to their solubility in fat or water.
4. Discuss conditions or factors that affect the absorption of vitamins in your digestive tract.
5. Explain how an antioxidant can protect your body against free radical damage.
6. Discuss at least five ways to conserve the vitamin content of fruits and vegetables during food
preparation and storage.
Module 8.2
1. Define all of the key terms in this module.
2. Identify the fat-soluble vitamins and foods that are rich sources of these micronutrients.
3. Explain a major function of each fat-soluble vitamin in the body.
4. Describe major deficiency and/or toxicity signs and symptoms for each fat-soluble vitamin.
Module 8.3
1. Define all of the key terms in this module.
2. Explain how most B vitamins function as coenzymes.
3. List major functions and food sources for each water-soluble vitamin.
4. Describe major deficiency and/or toxicity signs and symptoms for each water-soluble vitamin.
Module 8.4
1. Define all of the key terms in this module.
2. Identify lifestyle practices associated with increased risk of certain cancers.
3. Identify foods that may increase your risk of cancer.
4. Explain why it may not be useful to take dietary supplements for cancer prevention.
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Nutrition Essentials: A Personal Approach
Unit Outline
UNIT OUTLINE
I. Introducing Vitamins (Module 8.1)
A. What’s a Vitamin?
1. A vitamin is an organic micronutrient
a. Regulates certain processes in the body
b. Isn’t made by your body
c. Occurs naturally in commonly eaten foods
d. Prevents a specific deficiency disorder
2. Vitamin Deficiencies
a. Diet consistently lacks the micronutrient
b. Your cells store vitamins to some extent
c. Body tissue levels of the vitamin become depleted and signs and symptoms
of the nutrient’s deficiency disease can occur
3. Vitamin Toxicities
a. Vitamin excesses can lead to toxicity signs and symptoms
b. Occurs in people who take megadoses of vitamin supplements or consume
large amounts of vitamin0fortified foods regularly
B. Classifying Vitamins
1. Vitamins A, D, E, and K are fat-soluble vitamins
2. Vitamin C and the “B vitamins” are water-soluble vitamins
3. Excess fat-soluble vitamins don’t dissolve in watery substances, but can accumulate
in body fat or liver
4. Water-soluble vitamins are not as toxic as fat-soluble vitamins; can be removed by
the kidneys
C. Vitamins: Digestion and Absorption
1. Vitamins don’t undergo digestion; lose their ability to function
2. The small intestine absorbs vitamins; but not 100%
3. Bile enhances lipid as well as fat-soluble vitamin absorption
4. Large doses of vitamin supplements may be given to people unable to absorb
vitamins
D. Retaining the Vitamin Content of Foods
1. Purchase fresh produce when it’s in season or at local farmer’s markets
2. Eat fruits and vegetables when they are fresh
3. Cook fresh or frozen vegetable by microwaving, steaming, or stir-frying
4. Don’t overcook vegetables and minimize reheating
5. Don’t add fat to vegetables during cooking
6. Store canned food in a cool place
E. General Roles of Vitamins
1. Vitamins generally have more than one function
a. Bone health
b. Energy metabolism
c. Blood clotting
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Nutrition Essentials: A Personal Approach
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d. Amino Acid Metabolism
e. Antioxidant Defense
f. Immune Function
g. Red Blood Cell Formation
2. What is an antioxidant
a. A free radical “attacks” a vulnerable molecule such as DNA
b. The damaged molecule becomes the source of another free radical that
“strikes” another vulnerable molecule
c. The reaction repeats itself as another free radical forms and attacks another
vulnerable molecule, such as a protein
d. Antioxidants protect cells by giving up electrons to free radicals
e. Antioxidants protect molecules from being damaged by free radicals
II. Fat-Soluble Vitamins (Module 8.2)
A. Food groups of MyPlate contain good sources of fat-soluble vitamins
1. Oils
2. Fruits
3. Vegetables
4. Dairy
5. Grains
6. Proteins
B. Vitamin A
1. Includes retinol, preformed vitamin A – only in animal foods
2. Plants contain yellow-orange pigments – carotenoids
3. Carotenoids can be converted from beta-carotene into retinol
4. Carotenoids sometimes are referred to as provitamin A
5. Vitamin A participates in the processes of cell production, growth, and development
6. Animal foods such as liver, butter, fish, fish oils, and eggs are good sources of
preformed vitamin A
7. Beta-carotene, common carotenoids may function as beneficial antioxidants in the
body
8. Carotenemia, or yellowing of the skin results from excess beta-carotene in the body
9. Mucus-secreting epithelial cells are affected by a deficiency of vitamin A
10. Rods and cones of the retina need vitamin A (retinol), or night blindness will result
11. Epithelial cells of the cornea may become harden and stop producing mucus in the
cornea causing dry eye
12. The cornea is a clear covering that enables light to enter your eye
13. Vitamin A toxicity may cause
a. Headache
b. Nausea and vomiting
c. Visual disturbances
d. Hair loss
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e. Bone pain and fractures
f. During pregnancy, excess vitamin A is a teratogen (causes birth defects)
g. Diets rich in beta-carotene and other antioxidant carotenoids may lower the risk
of age-related macular degeneration (AMD), a leading cause of blindness in the
U.S.
h. Table 8.3 provides a summary of basic information about vitamin A
C. Vitamin D
1. Cod liver oil contains a fat-soluble substance need for proper bone health and to
prevent rickets (1922)
2. Children with rickets have bones that are soft and can become misshapen, and
vitamin D is a cure for rickets
3. Vitamin D is a hormone as well as a nutrient
4. How Your Body Makes Vitamin D (EC 8.1)
a. Your body can make vitamin D when your skin is exposed to the surf’s
ultraviolet (UV) radiation
b. Previtamin D (derived from cholesterol) is found in the skin and is unable to
function in your body until it’s activated
c. The liver and kidneys are critical for the activation of vitamin D
5. Vitamin D stimulates bone cells to form calcium phosphate, the hard major mineral
compound in bone tissue
6. Vitamin D regulates muscular and immune function and reducing inflammation
7. Fish liver oils, and fatty fish naturally contain vitamin D
8. Milk is fortified with vitamin D, as well as orange juice, some ready-to-eat cereal and
margarine
9. Table 8.4 list some food sources of vitamin D
10. You may obtain sun exposure to make vitamin D
11. The adult form of rickets is called osteomalacia, bones are soft and break easily
because of less-than-normal amounts of calcium
12. People who are at risk of osteomalacia may need to take a vitamin D supplement
and may also develop osteoporosis
13. The accumulation or excess of vitamin D can produce toxicity, and can cause the
intestines to absorb too much calcium
14. Kidney stones are signs and symptoms of vitamin D toxicity
15. Table 8.5 provides a summary of basic about vitamin D
D. Vitamin E
1. Your body only uses the alpha-tocopherol form of vitamin E
2. Alpha-tocopherol is an antioxidant that protects polyunsaturated fatty acids in cell
membranes from being damaged
a. A cell needs a healthy cell membrane to function properly
b. Free radicals can damage polyunsaturated fatty acids in cell membranes
c. Vitamin E donates a stabilizing particle to the free radical so it’s no longer
destructive
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Nutrition Essentials: A Personal Approach
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3. Table 8.6 lists some common foods that are sources of vitamin E
4. Damaged RBC membranes undergo hemolysis (break apart and die), and can cause
anemia (RBCs that don’t have enough hemoglobin)
5. Hemoglobin is the protein in RBCs that transports oxygen
6. Vitamin E has low toxicity, but excess may interfere with vitamin K’s role in blood
clotting
7. Vitamin E supplements is not likely to reduce your risk of cardiovascular diseases or
mild cognitive impairment
8. Table 8.7 provides a summary of basic information about vitamin E
E. Vitamin K
1. Vitamin K is important to produce blood clotting factors
2. Lack of vitamin K can result in excessive bleeding if you cut yourself
3. Warfarin decreases vitamin K’s ability to form blood clots
a. Liver needs vitamin K to make certain clotting factors
b. Normally clotting factors and platelets are inactive
c. Injury to blood vessels exposes damaged tissues
d. Inactive clotting factors become activated
4. Table 8.8 lists some foods that are sources of vitamin K
5. Bacteria that live in your body make vitamin K
6. People who have liver diseases or cystic fibrosis may have a vitamin K deficiency
7. Infants are born with low levels of vitamin K
8. Table 8.9 provides a summary of basics about vitamin K
III. Water-Soluble Vitamins (Module 8.3)
A. Introduction
1. Recall that water-soluble vitamins are thiamin, riboflavin, niacin, colic acid, B-6, B-12
pantothenic acid, biotin, and vitamin C
2. Most water-soluble vitamins have no function unless they’re in a coenzyme
3. What’s a coenzyme, and how does it function? (EC 8.2)
a. A coenzyme is a small molecule that helps an enzyme function
b. Some enzymes can’t function unless they bind to a specific coenzyme
c. When the coenzyme binds to the enzyme, the enzyme is activated
d. The active enzyme can split the molecule into two compounds
4. Foods usually contain B vitamins in their coenzyme form
5. The liver can store excesses of vitamin B-12
B. The Power Player Vitamins
1. Thiamin, riboflavin, and niacin are B vitamins that we refer to as “power players”
2. Your cells need these for energy
3. Thiamin deficiency disease is called beriberi
4. Ariboflavinosis is the riboflavin deficiency disorder
5. Niacin deficiency disease is pellagra
6. Food sources of power player vitamins include milk, yogurt, and other milk products
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Nutrition Essentials: A Personal Approach
Unit Outline
7. Review Tables 8.10–12 for vitamin content of selected foods
C. Vitamin B-6: Amino Acid Manager
1. Vitamin B-6 along with a coenzyme assist the body in amino acid metabolism to:
a. Make nonessential amino acids
b. Make glucose form certain amino acids
c. Produce heme, the iron-containing portion of hemoglobin
d. Make proteins that transmit messages between nerves
e. Convert a toxic amino acid homocysteine to a nonessential amino acid
2. Food sources of Vitamin B-6
a. Liver, meat, fish and poultry
b. Potatoes, bananas, spinach, and broccoli
c. Table 8.15 lists food with major sources of vitamin B-6
D. Folate and Vitamin B-12: DNA Duo
1. Folate refers to a family of related compounds that includes naturally occurring
“food folate” and folic acid
2. Needed to make coenzymes involved in DNA production
3. Requirements for folate and vitamin B-12 are high before birth, and in pregnancy,
infancy, and childhood (periods of rapid growth)
4. Without folate, RBC precursor cells that are in your bone marrow enlarge, but
cannot divide normally, and are unable to form new DNA
5. Megaloblastic anemia is characterized by large, immature RBCs that still have nuclei
and do not carry normal amounts of oxygen
6. Work together to make the amino acid methionine from the toxic amino acid
homocysteine
7. Maintaining myelin that wraps around parts of many nerves is a function of vitamin
B-12
8. Enriched grain products and fortified cereals are among the richest sources of folate
in the American diet (Table 8.16–17)
9. Absorbing Vitamin B-12 in Your Food (EC 8.3)
a. Vitamin B-12 is bound to a protein in an animal food
b. Before your small intestine can absorb this form of vitamin B-12 the bond
between the vitamin and this protein has to be broken
c. The action of HCl in the stomach frees the vitamin
d. The freed vitamin is picked up and carried by intrinsic factor produced by the
stomach
e. The carrier molecule transports vitamin B-12 to the last segment of the small
intestine where it is absorbed
f. The liver stores excesses of vitamin B-12
10. Folate and Vitamin B-12 Deficiencies
a. Pregnant women who are deficient in folate have high risk of giving birth to
infants with neural tube defects, such as spina bifida
b. Megaloblastic anemia results in immature RBCs that don’t carry oxygen properly
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Nutrition Essentials: A Personal Approach
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c. Common signs of vitamin B-12 deficiency include muscle weakness, sore mouth,
smooth and shiny tongue, memory loss and confusion, numbness, and tingling
sensations
d. Pernicious anemia is a form of anemia that features megaloblastic RBCs and
nerve damage
e. Deficiency in older adults results in the decline of HCl levels in the stomach,
affecting vitamin B-12 release from protein to which it’s bound in food
11. Table 8.18 summarizes information about folate and vitamin B-12
E. Panthothenic Acid, Biotin, and Choline
1. Deficiencies of these micronutrients are uncommon
2. Bacteria that live in the large intestine make biotin and the intestine may absorb
some of the vitamin
3. Table 8.19 summarizes basic information about pantothenic Acid, Biotin, and
Choline
F. Vitamin C: Collagen Connector
1. Vitamin C or ascorbic acid enables may enzymes to work
2. Vitamin C forms and maintains collagen, the protein that gives strength to
connective tissue
3. Your body needs vitamin C to:
a. Maintain the immune system
b. Produce bile
c. Make certain chemicals that transmit messages between nerves
d. Produce various hormones, including the “stress hormone” cortisol
4. Vitamin C also serves an antioxidant by donating electrons to stabilize free radicals
5. Calcium ascorbate and sodium ascorbate are forms of vitamin C
6. Table 8.20 lists some common foods and their vitamin C contents
7. Vitamin C is very unstable in the presence of heat, oxygen, light, alkaline
conditions, and the minerals iron and copper
8. Scurvy is a vitamin C deficiency that result from poorly formed and maintained
collagen
a. Swollen gums that bleed easily
b. Teeth that loosen and all out
c. Skin that bruises easily
d. Old scars that open
9. Exceeding the UL of the vitamin (2000 mg/day), can be toxic
10. Table 8.21 summarizes information about vitamin C
IV. Vitamins and Cancer (Module 8.4)
A. What’s Cancer?
1. A specific carcinogen such as a virus or toxic chemical harms the DNA
2. Cancer results when damage leads to rapid growth and unchecked cell division
3. Cancer refers to this group of cells
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Nutrition Essentials: A Personal Approach
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a. Malignant cancer cells divide repeatedly and frequently and don’t die
b. Masses of cells form malignant tumors
4. Some risk factors for cancer may include:
a. Age (over 65 years)
b. Family history of cancer
c. Tobacco use
d. Exposure to some forms of radiation
e. Diet
f. Alcohol use
g. Physical inactivity and excess body fat
B. The Role of Obesity and Diet in Cancer Development
1. Obesity is a risk factor for:
a. Breast cancer
b. Colon and rectum cancer
c. Kidney cancer
d. Pancreas cancer
e. Thyroid cancer
f. Gallbladder cancer
2. Alcohol consumption can put you at risk for cancers:
a. Mouth
b. Throat
c. Esophagus
d. Voice box
e. Liver
f. Colon
g. Rectum
h. Breast
3. Possible diet-related carcinogens can be outlined in Table 8.22
4. You can reduce your risk of cancer by
a. Avoiding exposure to tobacco smoke
b. Achieving and maintaining a healthy weight
c. Adopting a physical active lifestyle
d. Eating a healthy diet
e. Consuming a wide variety of vitamins in their natural state
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