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Chapter 11 – The Fat-Soluble Vitamins: A, D, E, and K
Learning Objectives
After completing Chapter 11, the student will be able to:
1. Identify the roles of vitamin A and describe the effects of vitamin A deficiency and toxicity.
2. List food sources of vitamin A and beta-carotene.
3. Describe the uses of vitamin D in the body and the effects of deficiency and toxicity.
Assignments and Other Instructional Materials
The following ready-to-use assignments are available in this chapter of the instructor’s manual:
• New! Case study
• Worksheet 11-1: Fat-Soluble Vitamins’ Equivalent Measurements
1
Other instructional materials in this chapter of the instructor’s manual include:
• Answer key for How To (p. 361) activity
• Classroom activities
• Worksheet answer keys (as appropriate)
Lecture Presentation Outline
4
“Of special interest to...” symbol key: = Hot Topic = Personal Health
= Health Care Professionals = Science Majors
Key to instructor resource annotations (shown to the right of or below outline topics):
PL = Available on Power Lecture DVD-ROM (ISBN 0538797592): V = video
TRA = Transparency acetates: 12e TRA = 12th edition, 11e TRA = 11th edition, 10e TRA = 10th edition
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I. Vitamin A (also known as retinol, retinal, retinoic acid) and Beta-Carotene 10e TRA 118
Vitamin A is found in the body in compounds known as retinoids: retinol, retinal, and retinoic acid. These have
functional roles in vision, healthy epithelial cells, and growth. Vitamin A deficiency is a major health problem
A. Roles in the Body
1. Vitamin A in Vision 10e TRA 119
a. Helps to maintain the cornea.
2. Vitamin A in Protein Synthesis and Cell Differentiation
a. Through cell differentiation, vitamin A allows cells to perform specific functions.
3. Vitamin A in Reproduction and Growth
a. Sperm development in men.
b. Normal fetal development in women.
4. Beta-Carotene as an Antioxidant
a. Beta-carotene helps protect the body from diseases, including cancer.
B. Vitamin A Deficiency - Because vitamin A is stored in the body, it would take a year or more to develop a
deficiency in the presence of inadequate intake.
1. Infectious Diseases
2. Night Blindness
3. Blindness
4. Keratinization
5. Deficiency disease is called hypovitaminosis A.
C. Vitamin A Toxicity – can occur with concentrated amounts of the preformed vitamin A from animal
foods, fortified foods, or supplements. Consuming excessive amounts of beta-carotene from supplements
can be harmful. Website HN 11-1
1. Bone Defects
a. Increased activity of osteoclasts causes weakened bones and contributes to osteoporosis and
fractures.
D. Vitamin A Recommendations
1. Expressed as retinal activity equivalents (RAE) because sources include all forms of retinoids and
beta-carotene.
E. Vitamin A in Foods 10e TRA 121; IM CI 11.2
1. Retinol is found in fortified milk, cheese, cream, butter, fortified margarine, and eggs.
2. Beta-carotene
a. Spinach and other dark green leafy vegetables (chlorophyll pigment masks the color).
II. Vitamin D – also known as 25-hydroxyvitamin D (calcidiol), 1,25-dihydroxy vitamin D (calcitriol), vitamin D3
(cholecalciferol), and vitamin D2 (ergocalciferol).
A. Roles in the Body
1. Vitamin D in Bone Growth
a. Helps to maintain blood levels of calcium and phosphorus.
b. Works in combination with other nutrients and hormones.
1. Vitamin A, vitamin C, and vitamin K.
2. Vitamin D in Other Roles
a. Immune system.
B. Vitamin D Deficiency 10e TRA 123
1. Factors that contribute to deficiency
a. Dark skin.
2. Rickets
1. Inadequate calcification of bones.
3. Misshapen bones including bowing of the legs.
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4. Enlargement of the ends of long bones.
3. Osteomalacia
a. Affects adults.
4. Osteoporosis
5. The Elderly
a. Deficiency is likely due to inadequate production and activation of vitamin D, a decreased
C. Vitamin D Toxicity
1. More likely to be toxic compared to other vitamins.
2. Vitamin D from sunlight and food is not likely to cause toxicity.
3. High-dose supplements may cause toxicity.
D. Vitamin D Recommendations and Sources PL V “New Vitamin D Guidelines”
2. Some research suggests vitamin D intake should be between 95 and 125 g per day.
3. Vitamin D in Foods IM CI 11.2
a. Fortified milk, butter, and margarine.
b. Cereals.
4. Vitamin D from the Sun 10e TRA 122, 124
a. Synthesized in the body from cholesterol.
III. Vitamin E (also known as alpha-tocopherol)
There are four different tocopherol compounds, but only the alpha-tocopherol has vitamin E activity in human
beings.
A. Vitamin E as an Antioxidant 10e TRA 125, 126
1. Stops the chain reaction of free radicals.
B. Vitamin E Deficiency
1. Primary deficiency due to inadequate intake is rare.
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b. Hemolytic anemia can be treated with vitamin E.
3. Symptoms
a. Loss of muscle coordination and reflexes.
C. Vitamin E Toxicity
1. Rare and the least toxic of the fat-soluble vitamins.
D. Vitamin E Recommendations – RDA adults: 15 mg/day.
E. Vitamin E in Foods
1. Polyunsaturated plant oils such as margarine, salad dressings, and shortenings.
2. Leafy green vegetables.
IV. Vitamin K (also known as phylloquinone, menaquinone, menadione, and naphthoquinone)
Vitamin K is unique in that half of human needs are met through the action of intestinal bacteria. Vitamin K is
A. Roles in the Body
1. Synthesis of blood-clotting proteins. 10e TRA 127
B. Vitamin K Deficiency
1. Symptoms include hemorrhaging.
C. Vitamin K Toxicity
1. Uncommon.
D. Vitamin K Recommendations and Sources
1. AI men: 120 g/day.
2. AI women: 90 g/day.
3. Vitamin K sources
a. Bacterial synthesis in the digestive tract.
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V. The Fat-Soluble Vitamins – In Summary IM CI 11.1, 11.3
The function of fat-soluble vitamins depends on the presence of other fat-soluble vitamins. There are many
interactions of fat-soluble vitamins with minerals. It is important to eat a wide variety of foods every day.
A. Free Radicals and Disease 11e TRA 24
1. Produced by normal body processes and environmental factors such as ultraviolet light, air pollution,
and tobacco smoke.
B. Defending against Free Radicals IM WS 11-2; Website HN 11-2
1. Limiting free radical formation.
2. Destroying free radicals or their precursors.
C. Defending against Cancer
1. Antioxidants may protect DNA from damage.
D. Defending against Heart Disease
1. Fruits and vegetables strengthen antioxidant defenses against LDL oxidation.
E. Food, Supplements, or Both?
1. Food and diet
a. Reduce saturated or trans-fat.
2. Supplements IM CA 11-2
3. High-antioxidant foods IM CA 11-3
a. Fruits – pomegranates, berries, and citrus.
b. Vegetables – kale, spinach, and Brussels sprouts.
c. Grains – millet and oats.
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Case Study
5
Joan is a 90-year-old Caucasian woman who has recently been diagnosed with osteoporosis after a recent fall that
broke her hip. She is 5 feet 4 inches tall and weighs 115 pounds. Lately she has been complaining about muscle pain
in her legs. She eats a limited diet due to a chronic low appetite. A recent blood test shows Joan’s serum vitamin D
level is below normal. Her daily diet includes juice or fruit and toast with butter for breakfast; cottage cheese and
fruit for lunch, and salad or frozen vegetable with meat or poultry for dinner. She does not like fish and drinks milk
only occasionally. Although she lives in New Mexico, she spends most days indoors. Joan has been taking a blood-
thinning medication since she was discharged from the hospital. She takes a daily multivitamin that contains 400 IU
vitamin D and 15 mg vitamin E.
1. What may be some contributors to Joan’s low vitamin D status?
2. Suggest at least two practical ways for Joan to improve her vitamin D status.
3. Based on her medical history and current medications, what advice would you offer Joan regarding her current
intake of vitamin E? Explain.
4. Which of the four fat-soluble vitamins discussed in this chapter play a role in bone health? List foods that are
good sources of each.
5. What cautions would you give Joan regarding her intake of high-vitamin K foods that pertain to her use of a
blood-thinning medication?
6. Using information in Highlight 11, explain some simple dietary strategies that could improve Joan’s intake of
antioxidants. Explain which supplements, if any, may be helpful as well.
Answer Key:
1. Decreased ability to make and activate vitamin D with advancing age; low intake of milk; lack of sun exposure.
Suggested Classroom Activities
Like the water-soluble vitamins, the fat-soluble vitamins are endlessly fascinating. Outside reading from the recent
literature can give the class the latest on many interesting topics. The advertising emphasis on antioxidants to sell
supplements is a hot topic that will likely generate student interest. Several vitamin activities have been presented in
Chapter 10 of this manual that can also be used in the study of this chapter. Please see Classroom Activities 10-3,
10-4, 10-5, 10-6, 10-7, 10-8, and 10-9.
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Classroom Activity 11-2: Examination of Nutrition Quackery Via the Internet
6
Key concept: Evaluation of online nutrition information Class size: Any
Materials needed: Computer workstations with Internet access
Instructions: Instruct students to obtain information about a questionable nutritional product such as a nutrient
supplement. To increase Internet skills, instruct students to obtain information via the Internet. Next, have students
evaluate the claims regarding the product using anti-quackery sites on the Internet (see Highlight 1 for ideas).
Classroom Activity 11-4: Antioxidant Research Analysis
7
Key concept: Antioxidants in heart disease/cancer Class size: Small to medium
Instructions: Ask each student to select a peer-reviewed research article on the benefits of antioxidant therapy in the
How To “Try It” Activities Answer Key
How to Convert International Units (IU) to Weight Measurements
1200 µg vitamin A (retinol), 15 µg vitamin D (cholecalciferol), 8.04 mg vitamin E (alpha-tocopherol)
Critical Thinking Questions
8
These questions will also be posted to the book’s website so that students can complete them online and e-mail their
answers to you.
1. You have been called by “The Today Show,” who has hired you to discuss facts about the fat-soluble vitamins.
As a new media expert, you have done your homework and contacted the American Dietetic Association to ask
about media training. They have given you all sorts of great information. You are ready to tackle this wonderful
opportunity!
What tips should a nutrition professional keep in mind when presenting information to the media? Write a
practice “fact sheet” on the fat-soluble vitamins that you could use as a basis for your presentation.
Answer: First, you learned that when talking to media experts, the nutrition professional should prepare about
three “sound bites” that are short and easy to understand at a variety of consumer levels.
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Vitamin D: Known as the sunlight vitamin, vitamin D is activated in the body and works as a hormone to
support bone growth and maintenance. Other functions include regulation of gene activity and cell growth.
These activities influence several other areas of human illness, health, and wellness.
While milk is fortified with vitamin D, other food sources include egg yolks and fatty fish. Far and above,
except for those that are bedridden, sunlight provides the best source of vitamin D.
Deficiency of vitamin D results in rickets, a bone disease that is common in third world countries. The body is
very capable of regulating the level of vitamin D in the body; however, when an individual over consumes
supplements of vitamin D with other sources, toxicity can occur.
2. You are currently taking care of a patient that is a 65 y/o female from Buffalo, New York. She presents with a
fractured spine and states that she has lived closed up, inside, and alone for quite some time now since her
husband died. Her appetite has been poor. From this information, what nutrient or nutrients might she be
missing? What are your suggestions for her?
Answer: Focusing on this chapter and the fat-soluble vitamins, one would focus on vitamin D and its role in
bone health. As indicated from the small vignette, the patient has lived inside in an area that generally does not
get a great deal of sunlight. She also indicates that she stayed inside and kept to herself after her husband died.
3. Vitamin A is a fat-soluble vitamin important for vision, cell differentiation, and growth and development.
Discuss the different forms of vitamin A and its precursors and how they are activated. Then discuss the variety
of roles that vitamin A plays in the body.
Answer: There are two types of vitamin A: the active form, which is generally available from animal sources
and occurs as three different compounds, retinol, retinal, and retinoic acid; and the precursor to active vitamin
A, known as beta-carotene, which is available from plant sources.
4. If an individual overdoes his intake of vitamins E and K, this can cause significant problems in the body.
Discuss the problem with too much vitamin E and vitamin K for an individual, physiologically.
Answer: Vitamin E is important in keeping the blood “thin” or helping to keep the blood from clotting. This
could be another role it plays in its protection or prevention of heart disease, as individuals that are more prone
to heart disease are also more prone to accumulate arterial plaque and developing blood clots.
5. Discuss the fat-soluble vitamins that play a role in bone health and outline their specific roles.
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Answer: Vitamins A, D, and K all have a known role in bone health. Vitamin D has long been known for its
role in bone development and maintenance, but as nutritional science has progressed, these other fat-soluble
vitamins have demonstrated a role in bone health as well.
IM Worksheet Answer Key
Worksheet 11-1: Fat-Soluble Vitamins’ Equivalent Measurements
1. Twice as much.
2. In the U.S., milk is fortified with 10 µg/quart of vitamin D, and there are 4 cups in a quart. If the glass holds 1
cup of milk, then 1 glass would contain 10 µg/4 = 2.5 µg = 100 IU vitamin D. Vitamin D AI for ages 9-50 = 5
µg/day, so you would need to drink 2 cups of milk to obtain the AI.
3. Alpha-tocopherol is the only form of vitamin E that is active in the body, and the other forms are neither able to
perform the same functions as alpha-tocopherol nor easily converted to alpha-tocopherol in the body.
4. Answers will vary; students may point out that about half of vitamin K needs are normally met by production of
the vitamin by GI tract bacteria.
5. Answers will vary.
Worksheet 11-2 – Answers will vary.
Worksheet 11-3: Chapter 11 Crossword Puzzle
Worksheet 11-4: Fat-Soluble Vitamin Review (Internet Exercise)
Canadian Information
9
11.1 Canadian Recommendations for Intake of Fat-Soluble Vitamins for Healthy People
11.2 Fat-Soluble Vitamins in Canadian Foods
In the past, Canada’s policy on enrichment differed from that of the United States for vitamins A and D. In Canada,
it is mandatory for vitamin D to be added to all cow’s milk that is sold as fluid milk, and vitamin A to be added to
11.3 Reference Daily Values for Fat-Soluble Vitamins
On food labels, the % Daily Value information provided for the fat-soluble vitamins (e.g., vitamin A) is based on
Canadian reference Daily Values (DV), otherwise known as the Recommended Daily Intake (RDI). RDI are
legislated in current nutrition labelling requirements found in the Food and Drug Regulations.
13
As shown in Table
11.1, the comparison between reference DV used in Canada and the United States, vitamin K is the only fat-soluble
vitamin with the same reference DV.
Table 11.1 Reference Daily Values for Fat-Soluble Vitamins Used in Canada for Persons 2 Years and Older
14
Compared to Reference Daily Values Used in the United States for Persons 4 Years and Older
15
Fat-Soluble Vitamin
Canadian Daily Value
(RDI)
American Daily Value
Conversion Factor
Vitamin A*
1000 RE
5000 IU
1 RE = 3 IU
Vitamin D*
5 g
400 IU
1 g = 40 IU
Vitamin E*
10 mg
30 IU
1 mg = 1.5 IU
Vitamin K
80 g
80 g
*Indicates different values used in Canada and the United States.
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RE = retinol equivalents; g = micrograms; mg = milligrams; IU = International Units
Highlight 11: Antioxidant Nutrients in Disease Prevention
The 2002 amendments to Canada’s Food and Drug Regulations allowed diet-related health claims on food labels for
the first time in Canada; however, as part of the regulations, the Guide to Food Labelling and Advertising does not
In collaboration, Health Canada and the Public Health Agency of Canada publish a series of consumer-friendly fact
sheets titled It’s Your Health that cover a wide range of health topics. One recent fact sheet on vitamin E
supplementation provides information on antioxidant benefits as well as potential health risks associated with high
intakes of vitamin E.
17
Canadian Web-Based Resources
1. The Heart and Stroke Foundation of Canada has an online tool called Heart & Stroke Risk Assessment™ that
allows you to profile your personal risk for heart attack or stroke and create an action plan for healthy living.
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Worksheet 11-1: Fat-Soluble Vitamins’ Equivalent Measurements
Vitamin A = 1 RAE (retinal activity equivalent) = 1 microgram of retinol = 3.33 IU (International Units)
= 12 micrograms of dietary beta-carotene = 2 micrograms of beta-carotene supplements
= 24 micrograms of other vitamin A precursor carotenoids
Vitamin D = 1 IU = vitamin D3 = 0.025 micrograms, 1 microgram of vitamin D3 = 40 IU
Vitamin E = 1 mg = 1 alpha-tocopherol unit
Vitamin K = DRI not defined but expressed as AI (Adequate Intake) = micrograms
There is so much discussion and confusion related to the measurements of fat-soluble vitamins that it becomes
difficult for one to explain what the measurements actually indicate. In the table listed above are the common
equivalent measurements for each of the fat-soluble vitamins. Consider these equivalent measurements when
answering the questions below.
3. When considering the fact that there are other tocopherols existing besides alpha-tocopherol in the body, why
can’t you just use a food supplement containing one of them to get your daily recommended intake of vitamin
E?
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Worksheet 11-2: Antioxidants
Consider the following questions listed below and perform the following search methods in order to find out
information to discuss the answers: traditional library search, database search, textbook search, and web-based
search engine search. See how the information you have gathered differs in both its amount and the quality of
information.
1. Which vitamins are considered to have antioxidant properties?
4. How does the body handle oxidative stress?
8. Is there a recommended allowance for the daily intake of dietary antioxidants?
9. Which food sources are considered to have the highest amount of antioxidant properties?
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Worksheet 11-3: Chapter 11 Crossword Puzzle
Across:
Down:
1. the vitamin D deficiency disease in children
characterized by inadequate mineralization of bone
6. abnormal drying of the skin and mucous membranes
8. bursting of red blood cells
9. a chronic inflammation of the skin’s follicles and
2. accumulation of keratin in a tissue; a sign of vitamin
A deficiency
3. high blood calcium that may develop from a variety
of disorders
4. progressive blindness caused by vitamin A
1 2
3
4 5
6 7
8
9
10
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Worksheet 11-4: Fat-Soluble Vitamin Review (Internet Exercise)
1. Match the vitamin with its pertinent information.
a. A
b. E
2. One retinol activity equivalent is equal to 10 mcg of beta-carotene.
a. True
b. False
3. Symptoms of vitamin A toxicity are dizziness and blurred vision.
4. Which of the following are ways that we obtain vitamin D?
5. The active form of vitamin K is alpha-tocopherol.
a. True
b. False
6. Which of the following individuals is at risk for decreased absorption of vitamin K?
