Vitamins ch9 and 11


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Vitamins ch9 and 11

  1. 1. Vitamins
  2. 2. Two Categories of Vitamins <ul><li>Fat-soluble </li></ul><ul><ul><li>A, D, E, K </li></ul></ul><ul><li>Water-soluble </li></ul><ul><ul><li>The 8 B vitamins, vitamin C </li></ul></ul>
  3. 3. Vitamin Storage in the Body <ul><li>Vitamin storage in the body </li></ul><ul><ul><li>Fat-soluble vitamins are stored in adipose cells </li></ul></ul><ul><ul><li>Water-soluble vitamins are not well stored, easily excreted by the kidneys </li></ul></ul>
  4. 4. Vitamin Toxicity <ul><li>Megadose = 10 times the RDA </li></ul><ul><ul><li>Toxic levels of vitamins are usually achieved only with supplements </li></ul></ul><ul><li>Although foods may be excellent sources of vitamins, it is difficult to have toxic effects without supplementation </li></ul><ul><li>Because fat-soluble vitamins are stored and excess water-soluble vitamins are excreted by the kidneys, toxicity from fat-soluble vitamins is more likely </li></ul>
  5. 5. Preserving Vitamin Content <ul><li>Keep fresh produce cool, away from light </li></ul><ul><li>Peel and cut only right before serving </li></ul><ul><li>Use soon after purchase </li></ul><ul><li>Frozen and canned products do provide substantial vitamin content still, particularly if use the fluid packed with it </li></ul><ul><li>For cooking, less water is best (steam, microwave, stir-fry) </li></ul>
  6. 6. Fig. 8.15 Processing grains reduces natural vitamin and mineral content. Some processed grain products are fortified, but much micronutrient content is not restored.
  7. 7. Vitamin A <ul><li>Vitamin A = retinol, retinal, retinoic acid </li></ul><ul><li>Preformed vitamin A = retinol </li></ul><ul><ul><li>Found in animal products (organ meat) </li></ul></ul><ul><li>Provitamin A </li></ul><ul><ul><li>Found in plant products </li></ul></ul><ul><ul><ul><li>Beta-carotene, lycopene </li></ul></ul></ul><ul><li>Only retinol can be toxic </li></ul>
  8. 8. Vitamin A <ul><li>Functions: </li></ul><ul><ul><li>Eyes </li></ul></ul><ul><ul><ul><li>Prevents night blindness </li></ul></ul></ul><ul><ul><ul><li>Protects mucus-producing cells in the eyes </li></ul></ul></ul><ul><ul><ul><ul><li>Helps prevent xerophthalmia (“dry eye”) </li></ul></ul></ul></ul><ul><ul><li>Growth/reproduction </li></ul></ul><ul><ul><ul><li>Vitamin A attaches to DNA to stimulate the production of proteins necessary for healthy growth </li></ul></ul></ul><ul><ul><li>Antioxidant: may protect against some cancers </li></ul></ul><ul><ul><ul><li>Lycopene and prostate cancer </li></ul></ul></ul>
  9. 9. Vitamin A <ul><li>Deficiency </li></ul><ul><ul><li>Common in countries with poor access to food </li></ul></ul><ul><li>Toxicity </li></ul><ul><ul><li>Caused by excessive intake of retinol </li></ul></ul><ul><ul><li>Acne cream, pregnancy </li></ul></ul>
  10. 10. Vitamin D: The Sunshine Vitamin <ul><li>Non-food source: sunlight exposure on skin </li></ul><ul><ul><li>About 25% of the time it takes to get a sunburn, 2-3 times per week </li></ul></ul><ul><ul><li>In Colorado, not between October and March </li></ul></ul><ul><li>Body converts a cholesterol derivative into inactive vitamin D when exposed to sun radiation </li></ul><ul><ul><li>Inactive vitamin D (also form found in supplemented foods/beverages) is activated in the kidneys </li></ul></ul>
  11. 11. Fig. 8.5
  12. 12. Vitamin D <ul><li>Function: encourages calcium absorption and deposition in bones </li></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Rickets – malformation of skeletal tissue, soft bones from inadequate calcium (“bowlegged”) </li></ul></ul><ul><ul><li>Osteoporosis – bone loss disease </li></ul></ul>
  13. 13. Vitamin E <ul><li>Tocopherols </li></ul><ul><li>Function: </li></ul><ul><ul><li>Most potent fat-soluble antioxidant, protects PUFAs and LDL from free radical damage </li></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Hemolytic anemia – preterm babies who do not have good vitamin E accumulation </li></ul></ul><ul><li>Food sources: vegetable oils, nuts </li></ul>
  14. 14. Fig. 8.8
  15. 15. Vitamin K <ul><li>Non-food source: bacteria in the large intestine </li></ul><ul><li>Function: maintains healthy levels of blood clotting factors </li></ul><ul><ul><li>“ koagulation” </li></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Newborns – sterile large intestine </li></ul></ul><ul><ul><li>Long-term antibiotic use </li></ul></ul>
  16. 16. Fig. 8.11
  17. 17. Vitamin C <ul><li>Ascorbic acid </li></ul><ul><li>Functions: </li></ul><ul><ul><li>Maintains healthy collagen </li></ul></ul><ul><ul><ul><li>Major structural protein in teeth, bones, tendons, blood vessels </li></ul></ul></ul><ul><ul><li>Antioxidant – prevents some free radical damage </li></ul></ul><ul><ul><ul><li>May help protect against cardiovascular disease, cancers, cataracts in the eye </li></ul></ul></ul><ul><ul><li>Immune system function </li></ul></ul>
  18. 18. Vitamin C <ul><li>So, does vitamin C cure colds? </li></ul><ul><ul><li>No, but…. </li></ul></ul><ul><ul><ul><li>Vitamin C can reduce the duration of cold symptoms by about 1 day </li></ul></ul></ul><ul><ul><li>Body is saturated with 200 mg/day </li></ul></ul><ul><ul><li>Supplements often provide 1000 to 2000 mg </li></ul></ul><ul><ul><li>Eat citrus! </li></ul></ul>
  19. 19. Vitamin C <ul><li>Deficiency: </li></ul><ul><ul><li>Scurvy – disease characterized by poor quality collagen </li></ul></ul><ul><ul><ul><li>Fragile capillary walls, easy bruising, poor wound healing, bone pain and fractures, diarrhea, pinpoint hemorrhages on arms and legs </li></ul></ul></ul><ul><li>RDA for cigarette smokers: 35mg extra </li></ul><ul><li>Toxicity: </li></ul><ul><ul><li>UL = 2 grams (2000 mg), stomach inflammation, diarrhea </li></ul></ul><ul><li>Cooking, water causes vitamin C loss </li></ul>Fig. 8.31
  20. 20. Coenzymes <ul><li>All B vitamins are coenzymes </li></ul>Fig. 8.13
  21. 21. Fig. 8.14
  22. 22. Thiamin <ul><li>Functions: </li></ul><ul><ul><li>Coenzyme in energy metabolism </li></ul></ul><ul><ul><li>Used in nutrition therapy with alcoholism (alcohol interferes with thiamin absorption) </li></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Beriberi </li></ul></ul><ul><ul><ul><li>Means “I can’t, I can’t” </li></ul></ul></ul><ul><ul><ul><li>Peripheral nerve disease, pain and paralysis of extremities, edema, muscle wasting </li></ul></ul></ul><ul><li>Sources: </li></ul><ul><ul><li>Animal protein foods, whole grains, enriched grain products, some vegetables and fruits </li></ul></ul><ul><ul><li>Easily lost in cooking water </li></ul></ul>
  23. 23. Riboflavin <ul><li>Function: </li></ul><ul><ul><li>Coenzyme in energy and protein metabolism </li></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Tissue inflammation and breakdown </li></ul></ul><ul><ul><li>Swollen, reddened tongue </li></ul></ul><ul><li>Food sources: milk, organ meats, whole or enriched grains, vegetables </li></ul><ul><li>Easily destroyed by light </li></ul><ul><ul><li>Milk in opaque containers </li></ul></ul>Fig. 8.18
  24. 24. Niacin <ul><li>Function: </li></ul><ul><ul><li>Coenzyme in system that converts protein into glucose </li></ul></ul><ul><li>Deficiency </li></ul><ul><ul><li>Pellegra – dermatitis, sometimes fatal effects on nervous system </li></ul></ul><ul><li>Tryptophan can be converted to niacin </li></ul><ul><ul><li>Milk has no niacin but is high in tryptophan </li></ul></ul><ul><ul><li>Milk can prevent deficiency </li></ul></ul>
  25. 25. Vitamin B6 <ul><li>Pyridoxine </li></ul><ul><li>Function: </li></ul><ul><ul><li>Coenzyme in protein metabolism in over 100 amino acid reactions </li></ul></ul><ul><ul><ul><li>Produces neurotransmitters, new amino acids, niacin from tryptophan, hemoglobin </li></ul></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Anemia </li></ul></ul><ul><ul><li>Nervous system problems (irritability, convulsions) </li></ul></ul><ul><ul><li>Infant formulas – if sterilized, destroys B6 </li></ul></ul>
  26. 26. <ul><li>Pantothenic acid </li></ul><ul><ul><li>Function: coenzyme in energy metabolism </li></ul></ul><ul><li>Biotin </li></ul><ul><ul><li>Function: coenzyme in the synthesis of fatty acids, amino acids, DNA </li></ul></ul><ul><ul><li>Some made by intestinal bacteria </li></ul></ul>
  27. 27. Folate <ul><li>Folic acid </li></ul><ul><li>Function: </li></ul><ul><ul><li>Coenzyme that transfers single carbons to build larger molecules </li></ul></ul><ul><ul><li>May help prevent heart disease </li></ul></ul>
  28. 28. Folate <ul><li>Deficiency: </li></ul><ul><ul><li>Macrocytic anemia </li></ul></ul><ul><ul><li>Chemotherapy drugs inhibit folate metabolism </li></ul></ul><ul><ul><li>Neural tube defects – inability of nerve cells to divide and make new cells </li></ul></ul><ul><ul><ul><li>Neural tube closes within 28 days of pregnancy </li></ul></ul></ul><ul><ul><ul><li>Spina bifida </li></ul></ul></ul><ul><ul><ul><li>Anencephaly </li></ul></ul></ul>
  29. 29. Fig. 8.26
  30. 30. Fig. 8.27
  31. 31. Folate <ul><li>Food sources: green leafy vegetables, legumes, tomatoes, enriched grains and flours </li></ul><ul><li>RDA: 400 micrograms, average intake 220 micrograms for women </li></ul>
  32. 32. Vitamin B12 <ul><li>Cobalamin </li></ul><ul><li>Function: </li></ul><ul><ul><li>Coenzyme in amino acid metabolism and hemoglobin production </li></ul></ul><ul><ul><li>Assists in placing lipid coat on nerve cells </li></ul></ul><ul><li>Deficiency: </li></ul><ul><ul><li>Pernicious anemia </li></ul></ul><ul><ul><li>Neurological problems – tingling in arms and legs, paralysis, mental decline </li></ul></ul>
  33. 33. Vitamin B12 <ul><li>Sources: </li></ul><ul><ul><li>Naturally only found in animal products </li></ul></ul><ul><ul><li>Fortified foods </li></ul></ul><ul><ul><li>Supplements/injections </li></ul></ul><ul><li>B12 is poorly absorbed without intrinsic factor made by stomach </li></ul>
  34. 34. Vitamin B12 <ul><li>People at risk for B12 deficiency: </li></ul><ul><ul><li>Elderly </li></ul></ul><ul><ul><ul><li>Reduced intrinsic factor production with age </li></ul></ul></ul><ul><ul><li>Vegans </li></ul></ul><ul><ul><ul><li>Eat no animal products, must use injections or enriched foods </li></ul></ul></ul><ul><ul><li>Infants nursed by vegan mothers </li></ul></ul><ul><ul><ul><li>Symptoms: diminished brain growth, spinal cord degeneration, anemia </li></ul></ul></ul>