Chapter 8: The Vitamins

1. Chapter 8: The Vitamins

2. Vitamins • Essential organic substances • Yield no energy, but facilitate energy-yielding chemical reactions • If absent from a diet, it will produce deficiency signs and symptoms

3. Function of Vitamins • Coenzyme • Antioxidant • Structure and formation of tissue

4. RDA’S • Recommended Dietary Allowances • Established for Average, HEALTHY Populations • Set higher than actual needs so most could meet needs by only consuming only 75% of RDA • What about taking more than RDA?

5. Fun Facts • Named in order of discovery • Plant and animal foods provide vitamins • Scientists believe they have discovered all the vitamins

6. Classification • Fat Soluble • A, D, E, K • Water Soluble • C • B’s - B1, B2, B3, B6, B12

7. Fat-Soluble Vitamins Overview • Dissolve in organic solvents • Not readily excreted; can cause toxicity • Absorbed along with fat • Concern for people with fat malabsorption

8. Vitamin A • Deficiency is most common cause of non-accidental blindness • Preformed • Retinoids • Found in animal products • Proformed • Carotenoids • Found in plant products

9. Functions of Vitamin A • Night blindness • Cell health • Growth, development, reproduction • Cardiovascular disease prevention • Cancer prevention

10. Vitamin A and Your Skin • Topical treatment and oral drug • Accutane (oral) and Retin-A (topical) • Can induce toxicity symptoms • Not recommended for pregnant women • Use only under supervision of a physician

11. Vitamin A from the Food Guide Pyramid

12. Deficiency of Vitamin A • Night blindness • Irreversible blindness • Follicular hyperkeratosis • Bumpy, rough, and dry, flaky skin

13. Who is at Risk For Deficiency • Breast fed infants • Those with poor vegetable intake • Urban poor and the Elderly • Alcoholics and people with liver disease • HIV, AIDS

14. Toxicity of Vitamin A • Large intake of vitamin A over a long period • Bone/muscle pain, loss of appetite, skin disorders, headache, dry skin, hair loss, increased liver size, vomiting • Spontaneous abortion, birth defects • May occur with as little as 3 x RDA of preformed vitamin A

15. Toxicity of Carotenoids High amounts of carotenoids in the bloodstream • Excessive consumption of carrots/squash/beta-carotene supplements • Skin turns a yellow-orange color

16. Vitamin D • Prohormone • Derived from cholesterol • Synthesized in skin with adequate sun exposure for Caucasians and other light skinned races

17. Functions of Vitamin D • Regulates blood calcium • Influences cell differentiation

18. Vitamin D causes Ca + Phos to deposit in the bones Strengthen bones Rickets- children Osteomalacia (soft bone) is rickets in the adult Role in Bone Formation

19. Food Sources of Vitamin D • Fatty fish (salmon, herring) • Fortified milk • Some fortified cereal

20. 5 ug/d (200 IU/day) for adults under age 51 10-15 ug/day (400 - 600 IU/day) for older Americans Infant are born with enough vitamin D to last ~9 months of age. The Adequate Intake (AI) for Vitamin D

21. Toxicity Warning • Vitamin D can be very toxic • Regular intake of 5-10x the AI can be toxic • Result from excess supplementation (not from sun exposure or milk consumption)

22. Vitamin E • Fat-soluble antioxidant • Resides mostly on cell membranes • Protects the cell from attack by free radicals • Protects PUFAs within the cell membrane and plasma lipoproteins • Prevents the alteration of cell’s DNA and risk for cancer development • Prevention of ischemic heart disease

23. Vitamin E, An Antioxidant

24. The More The Better? • Vitamin E is only one of many antioxidants • It is likely that the combination of antioxidants is more effective • Diversify your antioxidant intake with a balanced and varied diet • Megadose of one antioxidant may interfere with the action of another

25. Food Sources of Vitamin E • Plant oils • Wheat germ • Asparagus • Peanuts • Margarine • Nuts and seeds

26. RDA for Vitamin E • 15 mg/day for women and men • (=22 IU of natural source or 33 IU of synthetic form) • Average intake meets RDA 1 mg d--tocopherol = 0.45 IU (synthetic source) 1 mg d--tocopherol = 0.67 IU (natural sources)

27. Deficiency of Vitamin E • Hemolytic anemia • Rare

28. Toxicity of Vitamin E • Inhibit vitamin K metabolism and anticoagulants • Possible hemorrhage

29. Vitamin K (“Koagulation”) • Synthesized by the bacteria in the colon and are absorbed • Role in the coagulation process • Calcium-binding potential

30. Drugs and Vitamin K • Anticoagulant • Lessens blood clotting process • Antibiotics • Destroy intestinal bacteria • Inhibit vitamin K synthesis and absorption • Potential for excessive bleeding

31. Food Sources of Vitamin K • Liver • Green leafy vegetables • Broccoli • Peas • Green beans • Resistant to cooking losses • Limited vitamin K stored in the body

32. Overview of Water-Soluble Vitamins • Dissolve in water • Generally readily excreted • Subject to cooking losses • Function as a coenzyme • Participate in energy metabolism

33. Enrichment Act of 1941 and 1998 • Many nutrients lost through milling process of grains • Grain/cereal products are enriched • Thiamin, riboflavin, niacin, folate, iron • Enriched grains still deficient in B-6, magnesium and zinc

34. Thiamin B1 • Coenzyme • CHO metabolism

35. Deficiency of Thiamin Beriberi • Weakness, nerve degeneration, irritability, poor arm/leg coordination, loss of nerve transmission • Edema, enlarge heart, heart failure • Occurs where polished rice is the only staple

36. Food Sources of Thiamin • Wide variety of food • White bread, pork, hot dogs, luncheon meat, cold cereal • Enriched grains/ whole grains

37. RDA For Thiamin • 1.1 mg/day for women • 1.2 mg/day for men • Most exceed RDA in diet • Surplus is rapidly lost in urine; non toxic

38. Riboflavin B2 • Coenzymes • Participate in many energy-yielding metabolic pathways

39. Deficiency of Riboflavin • Seborrheic Dermatitis • Dermatitis around noses • Cracked lips, tongue

40. Food Sources of Riboflavin • Milk/products • Enriched grains • Liver • Oyster • Brewer’s yeast • Sensitive to uv radiation (sunlight) • Stored in paper, opaque plastic containers

41. RDA for Riboflavin • 1.1 mg/day for women • 1.3 mg/day for men • Average intake is above RDA • Toxicity not documented

42. Niacin B3 • Coenzyme • Metabolize CHO, Protein, Fat • Tissue respiration • Exchange of O2 and CO2

43. Deficiency of Niacin • Pellagra • 3 Ds • Occurs in 50-60 days • Decrease appetite & weight • Prevented with an adequate protein diet • Enrichment Act of 1941 • Only dietary deficiency disease to reach epidemic proportions in the U.S.

44. Food Sources of Niacin • Enriched grains • Beef, chicken, turkey, fish • 60mg tryptophan can be converted into 1 mg niacin

45. RDA for Niacin • 14 (mg) NE/day for women • 16 (mg) NE/day for men • Upper Level is 35 mg • Toxicity S/S: headache, itching, flushing, liver and GI damage • Megadose can lower LDL and TG and increase HDL

46. Pantothenic Acid • Essential for metabolism of CHO, fat, protein • Deficiency rare • Usually in combination with other deficiencies

47. Biotin • Metabolism of CHO and fat • Help break down certain amino acids • DNA synthesis

48. Vitamin B-6 • Coenzyme • Activate enzymes needed for metabolism of CHO, fat , protein • Synthesize nonessential amino acid • Synthesize neurotransmitters • Synthesize hemoglobin and WBC • Reduces Homocysteine levels

49. Food Sources of Vitamin B-6 • Meat, fish, poultry • Whole grains (not enriched back) • Banana • Spinach • Avocado • Potato • Heat sensitive

50. RDA for Vitamin B-6 • 1.3 mg/day for adults • 1.7 mg/day for men over 50 • 1.5 mg/day for women over 50 • Daily Value set at 2 mg • Average intake is more than the RDA • Athletes may need more • Alcohol destroys vitamin B6