Download Chapter 10 Fat-Soluble Vitamins Chapter Outline I. Understanding

Chapter 10
Fat-Soluble Vitamins
Chapter Outline
I. Understanding Vitamins. *Vitamins are organic substances the body needs in minuscule
amounts.
A. Anatomy of the vitamins. *Two classes of vitamins exist: fat-soluble vitamins (A,
D, E, and K) and water-soluble vitamins (B vitamin complex and vitamin C).
B. Fat-soluble versus water-soluble vitamins
C. Storage and toxicity
D. Provitamins
E. Vitamins in foods
Key terms: cartenodermia, megadose, provitamin, vitamin precursor
II. Vitamin A: The Retinoids. *Vitamin A comes from preformed retinoids and the
precursor carotenoids.
A. Forms of vitamin A
B. Storage and transport of vitamin A
C. Functions of vitamin A (Figure 10.6). *Vitamin A functions in vision, cell
differentiation, growth and development, and immune function.
1. Vitamin A and vision
2. Vitamin A in cell differentiation
3. Vitamin A and reproduction
4. Vitamin A and bone health
D. Dietary recommendations for vitamin A
E. Sources of vitamin A (Figure 10.10). *Sources of vitamin A include milk fat, egg
yolks, liver, green leafy and yellow-orange vegetables, and yellow-orange fruits.
F. Vitamin A deficiency. *Night blindness is an early symptom of vitamin A
deficiency that, if not treated, can result in permanent blindness.
1. Eyes
2. Skin
3. Other epithelial cells
4. Immune function
G. Vitamin A toxicity. *Vitamin A is toxic when taken in large doses, causing liver
damage and other problems.
1. Acne treatment
Key terms: retinoids, retinol, retinal, retinoic acid, carotenoids, provitamin A, retinyl esters,
retinol-binding protein, cornea, retina, rod cells, cone cells, opsin, rhodopsin, bleaching
process, dark adaptation, night blindness, iodopsin, stem cells, epithelial cells, epithelial
tissues, goblet cells, retinol activity equivalents (RAE), international units (IU), preformed
vitamin A, xerophthalmia, hyperkeratosis, keratin
III. The Carotenoids
A. Functions of carotenoids
1. Carotenoids as antioxidants
2. Carotenoids and vision
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3. Carotenoids and cancer
B. Absorption and storage of carotenoids
C. Sources of carotenoids
D. Carotenoid supplementation
Key term: free radical
IV. Vitamin D. *Vitamin D functions like a hormone and the body can synthesize it, but it is
still considered a vitamin.
A. Forms and formation of vitamin D (Figure 10.13)
B. Functions of vitamin D. *The primary function of vitamin D is the regulation of
blood levels of calcium.
1. Regulation of blood calcium levels
C. Dietary recommendations for vitamin D
D. Sources of vitamin D
1. Sunlight and vitamin D synthesis. *Vitamin D precursor is produced from
cholesterol when UV light hits the skin. Reactions in the liver and kidneys
are needed to produce a fully active vitamin D molecule.
2. Dietary sources of vitamin D (Figure 10.15). *Vitamin D in foods is
available mainly from fortified milk and other fortified products.
E. Vitamin D deficiency. *Vitamin D deficiency contributes to skeletal problems.
1. Rickets and osteomalacia
2. Osteoporosis (Figure 10.16)
3. Vitamin D and other conditions
4. Who is most at risk for a vitamin D deficiency?
F. Vitamin D toxicity. *Toxicity of vitamin D can develop with doses just a few
times larger than the AI level.
Key terms: antirachitic, calcitriol, parathyroid hormone, calcitonin, osteoclasts, osteoblasts,
rickets, osteomalacia, osteoporosis, hypercalcemia
V. Vitamin E. *Vitamin E is an important antioxidant in the body and may help reduce the
risk of chronic diseases such as heart disease and cancer.
A. Forms of vitamin E
B. Functions of vitamin E (Figure 10.19)
C. Dietary recommendations for vitamin E. *Vitamin E is found in vegetable oils
and foods made from those oils.
D. Sources of vitamin E (Figure 10.20)
E. Vitamin E deficiency. *Deficiency and toxicity of vitamin E are relatively rare.
F. Vitamin E toxicity
Key terms: tocopherol, tocotrienols, lipid peroxidation, gluathioine, hemolysis
V. Vitamin K
A. Functions of vitamin K (Figures 10.21 and 10.22). *Vitamin K is an important
factor in blood coagulation.
B. Dietary recommendations for vitamin K. *Although synthesized by intestinal
bacteria, most of the vitamin K in the body comes from dietary sources, especially
green leafy vegetables.
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C. Sources of vitamin K (Figure 10.24)
D. Vitamin K deficiency. *Vitamin K deficiency is rare, but newborns are
susceptible if not given an injection of vitamin K at birth.
E. Vitamin K toxicity. *Because the body excretes vitamin K easily, toxicity is
unlikely.
Key terms: phylloquinone, menaquinone, menadione
Classroom Activities
ACTIVITY 1: UNDERSTANDING THE DIFFERENCE BETWEEN FAT AND
WATER SOLUBLE VITAMINS
This activity can be given as a pre-quiz before reviewing vitamins to help students identify
the main differences between the two classifications of vitamins.
Directions: Students should identify whether the following functions relate to fat-soluble
vitamins, water-soluble vitamins, both, or neither.
1. Provides 4 kilocalories per gram.
Neither
2. Regulates the chemical reactions that allow individuals to obtain energy from
carbohydrates, fat, and protein.
Both
3. Organic compounds essential for normal functioning, growth, and maintenance of the
body.
Both
4. Vitamins A, D, E, and K.
Fat-soluble vitamins
5. Vitamin C and the B vitamins.
Water-soluble vitamins
6. These vitamins dissolve in water.
Water-soluble vitamins
7. These vitamins are transported through the body by fat.
Fat-soluble vitamins
8. Digestion in the stomach and small intestine release these vitamins from food.
Both
9. These vitamins travel directly into the bloodstream.
Water-soluble vitamins
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10. Micelles carry these vitamins and dietary fat to the brush border of the small intestine
for absorption.
Fat-soluble vitamins
11. As lipoproteins travel through the lymph and bloodstream, they carry these vitamins.
Fat-soluble vitamins
12. The kidneys filter out excesses of most of these vitamins.
Water-soluble vitamins
13. These vitamins are used as energy when the body is lacking in carbohydrates and fat.
Neither
14. These vitamins are excreted in the urine.
Water-soluble vitamins.
15. These vitamins are not needed daily because they can be stored in the body.
Fat-soluble vitamins
ACTIVITY 3: NAME THAT VITAMIN
This activity works well with smaller classes and can make note taking on vitamins more
interesting. This game is implemented within the lesson. Students will divide into teams
(teams of 5–7 work best). When students hear the word “Name” within the lesson, they
know that the question being asked is worth 10 points. It is a good idea for the instructor to
ask a student to keep score. Students can raise their hand to answer the question and the
person can discuss the answer with their team for 5 seconds. If the team answers the
question right, they get 10 points and if they answer it wrong, they get –10 points. If the
first group gets the answer wrong, the question is in play until two more groups answer it.
After that, the question is dead. The teams with the most points win. At the discretion of the
instructor, a reward for winning can be bonus points, free questions on tests or quizzes, or
just simply that the team has won. Instructors should inform students prior to the lesson that
the game will be played so that it is an incentive to read the book and understand the
material on vitamins. Students should not be allowed to use their book during the game.
After each Name question, the instructor can give the notes on that particular
question and elaborate on the specific vitamin. This game can be continued when reviewing
water-soluble vitamins. Questions that can be used in the Name game are the following:
NAME: This vitamin is best known for its role in vision but also is crucial for proper
growth, reproduction, immunity, and cell differentiation.
ANSWER: vitamin A
NAME: Name two out of the three active forms of vitamin A.
ANSWER: retinol, retinal, retinoic acid
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NAME: This is the colorful plant pigment that is a precursor of vitamin A.
ANSWER: carotenoid
NAME: Carotenoid that yields the most vitamin A.
ANSWER: beta-carotene
NAME: This is the organ that stores more than 90 percent of the body’s vitamin A.
ANSWER: liver
NAME: These are the paper-thin tissues that line the back of the eye. Retinol becomes a
functioning part of this in the eye.
ANSWER: retina
NAME: Name two other functions of vitamin A in the body.
ANSWER: maintains immune function, affects the reproductive process, and supports bone
health
NAME: Name two sources of vitamin A.
ANSWER: Refer to Figure 9.10.
NAME: What is one of the main reasons for vitamin A toxicity?
ANSWER: megadoses of nutritional supplements
NAME: Name two of the three colors that would indicate a food might be a source of
carotenoids.
ANSWER: deep yellow, orange, and red colors
NAME: This vitamin is also known as the sunshine vitamin.
ANSWER: vitamin D
NAME: Why is vitamin D called the sunshine vitamin?
ANSWER: Given sufficient sunlight, the body can synthesize vitamin D.
NAME: What is the precursor that can make vitamin D in the skin derived from?
ANSWER: cholesterol
NAME: A deficiency of vitamin D can cause a childhood bone disease called
___________________?
ANSWER: rickets
NAME: What is the predominant active form of vitamin D called?
ANSWER: calcitriol
NAME: Where in the body is vitamin D stored?
ANSWER: liver and adipose tissue
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NAME: What is vitamin D’s primary role in the body?
ANSWER: regulate blood calcium levels
NAME: True or False? Vitamin D is not considered an essential nutrient.
ANSWER: False. Some individuals have limited exposure to the sun.
NAME: A vitamin D deficiency can lead to the softening of the bones. What is this disease
called?
ANSWER: osteomalacia
NAME: This bone disease is characterized by a decrease in bone mineral density and the
appearance of small holes in bones.
ANSWER: osteoporosis
NAME: This vitamin acts as an antioxidant and its activity is enhanced by other
antioxidants.
ANSWER: vitamin E
NAME: Vitamin E is two sets of four compounds. Which compound is the only one that has
vitamin E activity in the body?
ANSWER: alpha-tocopherol
NAME: What happens to unabsorbed vitamin E?
ANSWER: It is excreted in the feces.
NAME: True or False? Excess vitamin E does not accumulate in the liver.
ANSWER: true
NAME: What is the terminology for the production of unstable, highly reactive lipid
molecules that contain excess amount of oxygen?
ANSWER: lipid peroxidation
NAME: Where is 90 percent of the body’s vitamin E stored?
ANSWER: adipose tissue
NAME: Name two functions of vitamin E.
ANSWER: stabilizes cell membranes, defends cells against free radical attack, helps
prevent cancer, protects the lungs, protects the tissues of skin, and maintains the
effectiveness of beta-carotene
NAME: Name two foods that are sources of vitamin E.
ANSWER: See Figure 9.20.
NAME: The primary purpose of this vitamin is blood clotting.
ANSWER: vitamin K
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NAME: What is another function of vitamin K? (One of the reasons explains why some
calcium supplements contain vitamin K.)
ANSWER: assists in bone formation
NAME: Where is vitamin K synthesized in the human body?
ANSWER: intestines
NAME: What is the primary form of dietary vitamin K?
ANSWER: phylloquinone
NAME: Which of these foods contains the most vitamin K: milk, corn oil, spinach, or
tomatoes?
ANSWER: spinach
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