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Chapter 11-1 Chapter 11 – The Fat-Soluble Vitamins: A, D, E, and K Learning Objectives After completing Chapter 11, the student will be able to: 11.1 11.2 11.3 11.4 H11 Identify the main roles, deficiency symptoms, and food sources for vitamin A. Identify the main roles, deficiency symptoms, and sources for vitamin D. Identify the main roles, deficiency symptoms, and food sources for vitamin E. Identify the main roles, deficiency symptoms, and sources for vitamin K. Describe how antioxidants defend against free radicals that contribute to diseases. a. Define the term free radical and explain its role in the development of disease. b. Describe the role of an antioxidant and identify dietary antioxidants. c. Discuss the roles of food and supplements as sources of dietary antioxidants. Glossary Chapter Key Terms acne: a chronic inflammation of the skin’s follicles and oil-producing glands, which leads to an accumulation of oils inside the ducts that surround hairs; usually associated with the maturation of young adults. alpha-tocopherol: the active vitamin E compound. beta-carotene (BAY-tah KARE-oh-teen): one of the carotenoids; an orange pigment and vitamin A precursor found in plants. calbindin: a calcium-binding transport protein that requires vitamin D for its synthesis. calciferol (kal-SIF-er-ol): vitamin D. carotenoids (kah-ROT-eh-noyds): pigments commonly found in plants and animals, some of which have vitamin A activity. The carotenoid with the greatest vitamin A activity is beta-carotene. cell differentiation (DIF-er-EN-she-AY-shun): the process by which immature cells develop specific functions different from those of the original that are characteristic of their mature cell type. chlorophyll (KLO-row-fil): the green pigment of plants, which absorbs light and transfers the energy to other molecules, thereby initiating photosynthesis. cornea (KOR-nee-uh): the transparent membrane covering the outside of the eye. epithelial (ep-i-THEE-lee-ul) cells: cells on the surface of the skin and mucous membranes. epithelial tissue: the layer of the body that serves as a selective barrier between the body’s interior and the environment. Examples are the cornea of the eyes, the skin, the respiratory lining of the lungs, and the lining of the digestive tract. erythrocyte (eh-RITH-ro-cite) hemolysis (he-MOLLuh- sis): the breaking open of red blood cells (erythrocytes); a symptom of vitamin E–deficiency disease in human beings. o erythro = red o cyte = cell o hemo = blood o lysis = breaking fibrocystic (FYE-bro-SIS-tik) breast disease: a harmless condition in which the breasts develop lumps, sometimes associated with caffeine consumption. In some, it responds to abstinence from caffeine; in others, it can be treated with vitamin E. o fibro = fibrous tissue o cyst = closed sac hemolytic (HE-moh-LIT-ick) anemia: the condition of having too few red blood cells as a result of erythrocyte hemolysis. hemophilia (HE-moh-FEEL-ee-ah): a hereditary disease in which the blood is unable to clot because it lacks the ability to synthesize certain clotting factors. hemorrhagic (hem-oh-RAJ-ik) disease: a disease characterized by excessive bleeding. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-2 intermittent claudication (klaw-dih-KAY-shun): severe calf pain caused by inadequate blood supply. It occurs when walking and subsides during rest. o intermittent = at intervals o claudicare = to limp keratin (KARE-uh-tin): a water-insoluble protein; the normal protein of hair and nails. keratinization: accumulation of keratin in a tissue; a sign of vitamin A deficiency. keratomalacia (KARE-ah-toe-ma-LAY-shuh): softening of the cornea that leads to irreversible blindness; a sign of severe vitamin A deficiency. menaquinone (men-ah-KWYN-own): the bacteria produced form of vitamin K; also called vitamin K2. mucous (MYOO-kus) membranes: the membranes, composed of mucus-secreting cells, that line the surfaces of body tissues. night blindness: slow recovery of vision after flashes of bright light at night or an inability to see in dim light; an early symptom of vitamin A deficiency. opsin (OP-sin): the protein portion of visual pigment molecules. osteocalcin (os-teo-KAL-sen): a calcium-binding protein in bones, essential for normal mineralization. osteomalacia (OS-tee-oh-ma-LAY-shuh): a bone disease characterized by softening of the bones. Symptoms include bending of the spine and bowing of the legs. The disease occurs most in adult women. o osteo = bone o malacia = softening phylloquinone (fil-oh-KWYN-own): the plant form of vitamin K; also called vitamin K1. pigment: a molecule capable of absorbing certain wavelengths of light so that it reflects only those that we perceive as a certain color. preformed vitamin A: dietary vitamin A in its active form. remodeling: the dismantling and re-formation of a structure. retina (RET-in-uh): the innermost membrane of the eye, composed of several layers, including one that contains the rods and cones. retinal (RET-ih-nal): the aldehyde form of vitamin A. retinoic (RET-ih-NO-ick) acid: the acid form of vitamin A. retinoids (RET-ih-noyds): chemically related compounds with biological activity similar to that of retinol; metabolites of retinol. retinol (RET-ih-nol): the alcohol form of vitamin A. retinol activity equivalents (RAE ): a measure of vitamin A activity; the amount of retinol that the body will derive from a food containing preformed retinol or its precursor, beta- carotene. retinol-binding protein (RBP): the specific protein responsible for transporting retinol. rhodopsin (ro-DOP-sin): a light-sensitive pigment of the retina that contains the retinal form of vitamin A and the protein opsin. o rhod = red (pigment) o opsin = visual protein rickets: the vitamin D–deficiency disease in children characterized by inadequate mineralization of bone (manifested in bowed legs or knock-knees, outward-bowed chest, and “beads” on ribs). A rare type of rickets, not caused by vitamin D deficiency, is known as vitamin D–refractory rickets. sterile: free of microorganisms, such as bacteria. teratogen (ter-AT-oh-jen): a substance that causes abnormal fetal development and birth defects. tocopherols (tuh-KOFF-uh-rawls): members of the vitamin E family having the chemical structure of a complex ring structure with a long saturated side chain. tocotrienols (TOE-koh-try-EE-nawls): members of the vitamin E family having the chemical structure of a complex ring structure with a long unsaturated side chain. vitamin A: all naturally occurring compounds with the biological activity of retinol, the alcohol form of vitamin A. vitamin A activity: a term referring to both the active forms of vitamin A and the precursor forms in foods without distinguishing between them. vitamin D2: vitamin D derived from plants in the diet also called ergocalciferol (ER-go-kal-SIF-er-ol). vitamin D3: vitamin D derived from animals in the diet or made in the skin from 7-dehydrocholesterol, a precursor of cholesterol, with the help of sunlight; also called cholecalciferol (KO-lee-kal-SIF-er-ol). xanthophylls (ZAN-tho-fills): pigments found in plants responsible for the color changes seen in autumn leaves. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-3 xerophthalmia (zer-off-THAL-mee-uh): progressive blindness caused by inadequate mucus production due to severe vitamin A deficiency. o xero = dry o ophthalm = eye xerosis (zee-ROW-sis): abnormal drying of the skin and mucous membranes; a sign of vitamin A deficiency. Antioxidant Nutrients Terms antioxidants: in the body, substances that significantly decrease the adverse effects of free radicals on normal physiological functions. free radical: an unstable molecule with one or more unpaired electrons. oxidants (OKS-ih-dants): compounds (such as oxygen itself) that oxidize other compounds. Compounds that prevent oxidation are called antioxidants, whereas those that promote it are called prooxidants. o anti = against o pro = for oxidative stress: a condition in which the production of oxidants and free radicals exceeds the body’s ability to handle them and prevent damage. phytochemicals: nonnutrient compounds found in plant-derived foods that have biological activity in the body. prooxidants: substances that significantly induce oxidative stress. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-4 Lecture Presentation Outline Key to instructor resource annotations (shown to the right of or below outline topics): Website = Available for download from book companion website: HN = student handout IM = Included in this instructor’s manual: CS = case study, WS = worksheet, CA = classroom activity Introductory/whole chapter resources: PL figure JPEGs; Test Bank; IM WS 11-1, 11-2, 11-3, HN 10-1 I. Vitamin A and Beta-Carotene (Figures 11-1 and 11-2) – Discuss the following: A. Roles in the Body 1. Vitamin A in Vision (Figure 11-3) a. Cornea b. Retina c. Rhodopsin 2. Vitamin A in Protein Synthesis and Cell Differentiation a. Cell differentiation b. Epithelial cells 1. Skin 2. Mucous membranes (Figure 11-4) 10e TRA 120 3. Vitamin A in Reproduction and Growth a. Sperm development b. Fetal development c. Growth d. Remodeling of the bone 4. Beta-Carotene as an Antioxidant – Protects the body from diseases B. Vitamin A Deficiency – Explain deficiency symptoms, including: 1. Infectious Diseases 2. Night Blindness 3. Blindness (Xerophthalmia) a. Xerophthalmia b. Xerosis c. Keratomalacia 4. Keratinization (Figure 11-5) C. Vitamin A Toxicity – Explain the effects of toxicity Website HN 11-1 1. UL for adults: 3000 g/day 2. Overconsumption of beta-carotene in foods (Figure 11-6) 3. Bone Defects 4. Birth Defects 5. Not for Acne a. Accutane b. Retin-A D. Vitamin A Recommendations IM CS 11-1 1. Retinal activity equivalents (RAE) 2. RDA for men: 900 g RAE/day 3. RDA for women: 700 g RAE/day E. Vitamin A in Foods (Figure 11-7) 1. Retinol is found in fortified milk, cheese, cream, butter, fortified margarine, and eggs 2. The Colors of Vitamin A Foods – Beta-carotene sources a. Spinach and other dark green leafy vegetables b. Deep orange fruits like apricots and cantaloupe c. Deep orange vegetables like squash, carrots, sweet potatoes, and pumpkin d. White foods are typically low in beta-carotene e. Vitamin A is poor in fast foods and foods with the xanthophyll pigments (beets, corn) 3. Vitamin A-Rich Liver – Liver is rich in vitamin A 4. Golden Rice- Genetically modified rice as significant source of beta-carotene for developing countries © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-5 II. Vitamin D (Figure 11-8) – Discuss the following: 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 2. Vitamin D in Other Roles a. Immune system b. Brain and nervous system c. Pancreas, skin, muscles, cartilage, and reproductive organs B. Vitamin D Deficiency IM CS 11-2 1. Discuss factors that contribute to deficiency 2. Rickets (Figure 11-9) a. Affects mainly children worldwide b. Describe deficiency symptoms 3. Osteomalacia – Define and explain osteomalacia 4. Osteoporosis – Define and explain osteoporosis 5. The Elderly – Discuss how vitamin D deficiency impacts elderly individuals C. Vitamin D Toxicity 1. Discuss toxicity causes and symptoms 2. UL for adults: 100 g/day or 4000 IU/day 3. Toxicity disease is called hypervitaminosis D D. Vitamin D Recommendations and Sources 1. Current recommendations: a. 15 g (600 IU) per day for those 19-70 b. 20 g (900 IU) per day for those older than 70 2. Vitamin D in Foods a. Fortified milk, butter, and margarine b. Cereals c. Chocolate mixes d. Veal, beef, egg yolks, liver, fatty fish and their oils e. Vegans may need fortification or supplements if they do not have adequate sun exposure 4. Vitamin D from the Sun (Figure 11-10) a. Synthesized in the body from cholesterol b. SPF of 8 or above prevents the synthesis of vitamin D from sunlight c. Can be obtained from tanning beds depending on type of UV radiation 5. Vitamin D from Supplements – beneficial for some elderly & others with inadequate skin synthesis III. Vitamin E – Discuss the following: A. Vitamin E as an Antioxidant 1. Stops the chain reaction of free radicals 2. Protection of polyunsaturated fatty acids and vitamin A 3. Protects against the oxidation of LDLs B. Vitamin E Deficiency 1. Primary deficiency rare 2. Erythrocyte hemolysis 3. Symptoms a. Loss of muscle coordination and reflexes b. Impaired vision and speech c. Nerve damage d. Erythrocyte hemolysis 4. Fibrocystic breast disease and intermittent claudication seem to respond to vitamin E treatment C. Vitamin E Toxicity 1. Rare and the least toxic of the fat-soluble vitamins 2. UL for adults: 1000 mg/day 3. May augment the effects of anticlotting medication © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-6 D. Vitamin E Recommendations – RDA for adults: 15 mg/day E. Vitamin E in Foods 1. Polyunsaturated plant oils such as margarine, salad dressings, and shortenings 2. Leafy green vegetables 3. Wheat germ 4. Whole grains 5. Liver and egg yolks 6. Nuts and seeds 7. Easily destroyed by heat and oxygen IV. Vitamin K – Discuss the following: A. Roles in the Body 1. Synthesis of blood-clotting proteins (Figure 11-11) 2. Synthesis of bone proteins that regulate blood calcium 3. Without vitamin K, a hemorrhagic disease may develop 4. Hemophilia is a hereditary disorder and is not cured with vitamin K 5. Allows osteocalcin to bind to bone minerals B. Vitamin K Deficiency 1. Symptoms include hemorrhaging 2. Secondary deficiencies may occur with use of antibiotics 3. Newborn infants receive a single dose of vitamin K at birth because of a sterile intestinal tract C. Vitamin K Toxicity 1. Uncommon 2. No known toxicity symptoms 3. High doses can decrease the effectiveness of anticlotting medications D. Vitamin K Recommendations and Sources IM CA 11-1 1. AI for men: 120 g/day 2. AI for women: 90 g/day 3. Vitamin K sources a. Bacterial synthesis in the digestive tract b. Significant food sources 1. Liver 2. Leafy green vegetables and cabbage-type vegetables 3. Milk V. Highlight: Antioxidant Nutrients in Disease Prevention A. Free Radicals and Disease – Describe the role of free radicals in disease (Figure H11-1) B. Defending against Free Radicals IM WS 11-4; Website HN 11-2 1. Limiting free-radical formation 2. Destroying free radicals or their precursors 3. Stimulating antioxidant enzyme activity 4. Repairing oxidative damage 5. Stimulating repair enzyme activity 6. Supporting a healthy immune system C. Defending against Cancer IM CA 11-2 1. Vitamin C seems to protect against esophageal cancer, but acts as a prooxidant at high doses 2. Vitamin E and carotenoids from foods might be protective D. Defending against Heart Disease 1. Vitamin E reduces LDL oxidation, inflammation, arterial injuries, & blood clotting 2. Vitamin C may reduce LDL oxidation, raise LDL, & lower cholesterol & blood pressure E. Food, Supplements, or Both? 1. Food and diet a. Reduce saturated or trans-fat b. Select foods rich in omega-3 fatty acids c. Fruits and vegetables offer antioxidants among other vitamins and minerals © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-7 2. 3. d. Emphasize whole grains and limit refined grains e. Exercise, control weight, and eliminate smoking to prevent disease Supplements a. Not enough data to confirm benefits of supplements only b. Contents of supplements are limiting c. Still need research to define optimum and dangerous levels with supplements High-antioxidant foods a. Fruits b. Vegetables c. Grains d. Legumes e. Nuts IM CA 11-3 IM CA 11-4 Case Studies Case Study 11-1: Supplemental Vitamin A1 Beth H. is a 29-year-old professional woman with a family history of osteoporosis. She weighs 135 pounds and is 66 inches tall. She eats a varied diet that includes meat, fish, and poultry and she consumes at least 2 cups of low-fat milk or yogurt most days. She drinks a small glass of orange juice every morning and typically eats about 2 cups of vegetables daily. Every day she takes a daily multivitamin that contains 10,000 IU vitamin A (as beta-carotene), and now she is wondering if this may be necessary or even harmful. 1. 2. 3. 4. 5. 6. According to the current RDA for vitamin A included in this chapter, how much vitamin A does Beth need each day? Using the formula in this chapter, show how Beth can convert the vitamin A in her supplement into RAE units. Then use this formula to calculate the amount of micrograms RAE Beth gets each day from her supplement. Use Figure 11-8 to estimate how much vitamin A (in micrograms RAE) Beth can reasonably expect to receive from her usual diet. Considering her family history and age, what are reasons that Beth should avoid excessive intakes of vitamin A in supplement form? What might be Beth’s reasons to continue taking her multivitamin supplement, which contains vitamin A as beta-carotene? What might be her reasons not to continue taking this supplement? Answer Key 1. 700 micrograms RAE 2. 1 IU beta-carotene supplement = 0.15 micrograms RAE. Beth gets 10,000 IU beta-carotene from her supplement × 0.15 micrograms RAE = 1500 micrograms RAE. 3. Answers will vary; should include vitamin A from fruit, vegetables, milk, and yogurt. Reasonable estimate is between 500 and 1000 micrograms RAE. 4. She has a family history of osteoporosis and excessive preformed vitamin A (retinol) can weaken bones and increase risk for fractures; she is of child-bearing age and excess preformed vitamin A during pregnancy can increase the risk for birth defects. 5. Answers will vary and may include that she is also getting other nutrients in her multivitamin that she might be missing; or that vitamin A in the form of beta-carotene is less toxic than preformed (retinol) vitamin A. 6. Answers may vary and may include: She gets adequate vitamin A in her usual diet; her diet is balanced, so she probably is getting a balanced intake of other nutrients as well; excess amounts of beta-carotene in supplement form act as prooxidants and can be harmful. 1 Contributed by Barbara Quinn. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-8 Case Study 11-2: Low Serum Vitamin D 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 64 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 dislikes most fish except canned tuna and she often drinks a glass of fortified milk before going to bed at night. 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 is 7-dehydrocholesterol? a. an hydroxylation by product of vitamin D metabolism b. the final product in the degradation of active vitamin D c. the form of vitamin D most often found in foods d. a vitamin D precursor manufactured in the liver e. the active form of vitamin D formed in the kidneys 2. Where does the final hydroxylation necessary for the activation of vitamin D occur? a. small intestine b. skin c. kidney d. liver e. spleen 3. Of the foods Joan eats, which is the best source of vitamin D? a. meat b. poultry c. vegetables d. fortified milk e. fruit 4. If Joan wants to increase her intake of Vitamin A, which of the following foods would be best? a. broccoli b. watermelon c. poultry d. tofu e. sweet potatoes 5. Because Joan is concerned about skin cancer, she uses a sunscreen when she is outside. At what SPF level will sunscreen start to interfere with vitamin D synthesis? a. 2 b. 8 c. 16 d. 32 e. 64 6. Joan is taking a vitamin E supplement that provides 15 mg. What is the UL for vitamin E in mg/day? a. 200 b. 400 c. 600 d. 800 e. 1000 © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-9 7. Since she is on a blood thinner, Joan has been warned about her intake of foods rich in vitamin K. Which of the following food groups is rich in vitamin K? a. freshwater fish b. ground beef c. dark green leafy vegetables d. lunch meats e. poultry Answer Key 1. d 2. c 3. d 4. e 5. b 6. e 7. c Suggested Classroom Activities Critical Thinking Questions2 1. Explain how fat-soluble vitamins contribute to the overall health of the body. 2. What is the major idea behind fortification of food products with vitamin D in the United States? 3. An individual is placed on antibiotic therapy. For which vitamin deficiency is he/she at greatest risk? Why might this occur? How can this be prevented? 4. Discuss the three associated bone diseases for which vitamin D metabolism is of clinical relevance. 5. Why is vitamin K given to newborns upon delivery? What happens if the newborn does not get the injection? 6. An individual consumes a large amount of vitamin A food sources and his/her skin turns yellow. Is this clinically significant? Why or Why not? Answer Key 1. Each of the fat-soluble vitamins plays a role in helping maintain the overall health of the body. Vitamin A plays a significant role in immune function (as an antioxidant), vision, skin integrity, and growth and development. Vitamin D plays a significant role in bone health and endocrine function. Adequate endogenous vitamin D formation requires adequate renal function and sunlight. Vitamin E plays a significant role in immune function, in red blood cell functioning, and as an antioxidant. Vitamin K plays a significant role in bone health and coagulation. Some of the fat-soluble vitamins are even thought to have “hormone”-like effects due to their various metabolic functions. Because some fat-soluble vitamins may also share common pathways affecting blood coagulation, it is important to have a balanced amount of fat-soluble vitamins in the body to maintain adequate function. Fat-soluble vitamins also interact with certain minerals (zinc, calcium, and phosphate) to facilitate metabolic processes. 2. 2 Food products are fortified with vitamin D in the U.S. in order to provide a stable, consistent source of the vitamin for the general population. There are few natural food sources, and not everyone can maintain adequate blood levels through skin synthesis alone. Fortified food sources high in vitamin D include dairy food products. Many people do not consume adequate amounts of this vitamin because they limit their dairy intakes due to either possible intolerance issues and/or personal preferences. Consumption of dairy products has declined in Contributed by Daryle Wane. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-10 recent years due to these issues, so the fortification process ensures that even with a more limited intake of these items, vitamin D levels are consistent. 3. An individual who is placed on antibiotic therapy is at risk to develop a vitamin K deficiency. This occurs because antibiotics can kill off intestinal bacteria that are necessary for the active formation of vitamin K in the intestinal tract. Many individuals who are prescribed antibiotics are also advised to consume yogurt and/or other sources of probiotics to minimize this destructive process. 4. Rickets is a disease state associated with a clinical vitamin D deficiency in children. Structural integrity of the bones is diminished, leading to characteristic bowed legs and beaded ribs. The occurrence of a clinical vitamin D deficiency in adults is called osteomalacia. This disease process results in deformities and painful bone disease. Osteoporosis, which is manifested by decreased bone mineral density, can result in loss of height and increased fractures. Individuals who do not consume adequate amounts of vitamin D are at risk for bone fractures due to accompanying calcium loss. 5. A vitamin K injection is recommended for all newborns in order to provide needed vitamin K until its intestinal production by bacteria begins. Since the infant is born with a sterile gut, there are no bacteria present to start this bodily process. A one-time injection is all that is required. If the injection is not given, then the newborn is at risk to develop a bleeding disorder resulting in hemorrhagic disease of the newborn. Clinical evidence provides support for the risk of this fatal type of hemorrhage in the absence of vitamin K. 6. There are several chemical compounds that have vitamin A activity, the most common of which are carotenoids, of which beta-carotene is most easily recognized. If an individual consumes a large amount of foods that are high in beta-carotene, the skin may turn yellow, but this is not clinically significant. Beta-carotene serves as a vitamin A precursor in the body and thus not all of it is converted into vitamin A. It is important to note the source of vitamin A compounds since if vitamin A is provided in the form of supplements, this can prove to be clinically significant. Remember that vitamin A is a fat-soluble vitamin and as such can be stored in the body, leading to toxic levels. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-11 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 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. 1. If you obtained your daily vitamin A intake from a precursor carotenoid source other than beta-carotene, how much would you have to consume as compared with obtaining your daily vitamin A from a dietary source of beta-carotene? 2. How many International Units (IU) of vitamin D are contained in a glass of milk and how many glasses of milk would you have to drink in order to get the daily recommended intake of vitamin D? 3. Considering the fact that there are other tocopherols besides alpha-tocopherol present in the body, why can’t you just use a food or supplement containing one of them to get your daily recommended intake of vitamin E? 4. Since vitamin K does not have an RDA or a specific equivalent measurement stated like the other fat-soluble vitamins, does it mean that the relative proportion contained in foods is less important? 5. Select one food item that you take in on a daily basis and then determine the relative equivalent measurements for the fat-soluble vitamins indicated above. Note whether or not the food item that you have selected meets the recommended dietary intakes for that nutrient. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-12 Worksheet 11-2: Chapter 11 Crossword Puzzle 1 2 3 4 5 6 7 8 9 10 11 12 Across: Humans can make approximately _____ of their requirement for vitamin K. 5. Vitamin A toxicity is usually associated with consuming _____. 7. Vitamin A is essential to _____, wherein each cell is developed to perform a particular function. 9. The only form of vitamin E that is active in the human body 10. _____ injections are given to newborns due to their sterile intestinal tracts. 12. Antioxidants help to protect the body against _____. 2. Down: The “sunshine vitamin” _____-soluble vitamins require bile for digestion and absorption. 4. Primary source of vitamin E in the diet 6. Precursor to vitamin A found in deep orange and dark green leafy vegetables 8. Vitamin D-deficiency disease 11. Almost all of the fat-soluble vitamins have a role in maintaining _____ health. 1. 3. © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-13 Worksheet 11-3: Fat-Soluble Vitamin Review (Internet Exercise) Instructions: Go to this website to answer questions 1-6: http://www.ext.colostate.edu/pubs/foodnut/09315.html. 1. a. b. c. d. A deficiency of which vitamin can cause excessive bleeding? A E D K 2. One retinol activity equivalent is equal to 10 micrograms of beta-carotene. a. True b. False 3. Symptoms of vitamin A toxicity include dizziness and blurred vision. a. True b. False 4. What is a good source of vitamin D? a. sunflower seeds b. olive oil c. fortified milk d. orange-colored vegetables 5. The active form of vitamin K is alpha-tocopherol. a. True b. False 6. Which situations will make an individual at risk for vitamin K deficiency? Select all that apply. a. taking antibiotics for an infection b. having repeated bouts of diarrhea c. eating large amounts of cruciferous vegetables d. receiving anticoagulant therapy © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Chapter 11-14 Worksheet 11-4: Antioxidants Consider the questions listed below and perform the following search methods in order to locate information to help answer them: 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? 2. Why does oxygen pose a threat to cell structures? 3. What is meant by the concept of free radicals? 4. How does the body handle oxidative stress? 5. Are there differences in dietary antioxidants vs. antioxidants found in dietary supplements? 6. Is there clinical evidence that antioxidants improve health outcomes? 7. Do foods differ in their antioxidant composition? 8. Is there a recommended allowance for the daily intake of dietary antioxidants? 9. Which food sources are considered to have the highest levels of antioxidant properties? 10. How do antioxidants function as stable entities in the body? © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.