Chapter 7 The Vitamins

1. Chapter 7The Vitamins Nutrition: Concepts & Controversies, 12e Sizer/Whitney

2. Learning Objectives • List the fat-soluble and water-soluble vitamins, and describe how solubility affects the absorption, transport, storage, and excretion of each type. • Explain how vitamins and minerals work in combination to maintain the health of the bones. • Name some functions of vitamin D not associated with the bones.

3. Learning Objectives • Define the term antioxidant, and name the vitamins that act as antioxidants in the body. • Discuss the roles of B vitamins in body tissues, and explain in a general way how B vitamins assist with energy metabolism. • Present arguments both for and against vitamin fortification of foods.

4. Learning Objectives • Suggest foods that can help to ensure adequate vitamin intakes without providing too many calories. • Justify this statement: “It is better to get vitamins from food than from supplements.” • List some valid reasons why supplements may be required by some people.

5. Definition and Classification of Vitamins • Vitamin • Essential, noncaloric, organic • Role of vitamins • Vitamin precursors • Classes • Absorption • Roles

6. Vitamin Names

7. Characteristics of the Fat-Soluble and Water-Soluble Vitamins

8. The Fat-Soluble Vitamins • A, D, E, and K • Food sources • Storage • Toxicity • Deficiency • Roles within the body

9. Vitamin A • Precursor • Beta-carotene • Active forms in the body • Retinol • Retinal • Retinoic acid • Food sources

10. Vitamin A – Roles and Deficiency • Gene regulation • Retinoic acid • Eyesight • Process of light perception • Maintenance of healthy cornea • Rhodopsin molecule

11. An Eye

12. Vitamin A – Roles and Deficiency • Night blindness • Deficiency • Xerophthalmia and blindness • Keratinization • Deficiency • Cell differentiation • Immune function • Growth

13. Vitamin A – Deficiency and Toxicity • Deficiency • Worldwide problem • Blindness • HIV • Toxicity • Symptoms • food sources • Liver

14. Vitamin A – Deficiency and Toxicity • Toxicity • Supplements • Higher risk groups • Recommendations • DRI recommendation based on body weight • Food sources • Animal origin • Liver • Plant origin

15. Vitamin A Deficiency and Toxicity

16. Vitamin A – Snapshot

17. Beta-Carotene • Plant-based foods • Colorful groups • Macular degeneration • Dietary antioxidant • Measuring beta-carotene • Retinol activity equivalents (RAE) • Toxicity • Food sources

18. Excess Beta-Carotene Symptom: Discoloration of the Skin

19. Vitamin D • Body can synthesize all it needs • Sunlight • Transformation • Liver and kidneys • Estimated deficiency prevalence

20. Vitamin D – Roles • Bone integrity • Hormone • Dangers with deficiency

21. Vitamin D – Too Little, Too Much • Deficiency • Rickets • Recommendations for prevention • Osteomalacia • Recommendations • Toxicity • Signs of toxicity

22. Rickets

23. Vitamin D • Ultraviolet B light rays • Cholesterol • Sunbathing risks • Sunscreen • Exposure times • Intake recommendations • Food sources

24. Factors Affecting Vitamin D Synthesis

25. Vitamin D - Snapshot

26. Vitamin E • Roles of vitamin E • Antioxidant • Deficiency • Symptoms • Toxicity • Dietary intake vs. supplemental intake • Recommendations • Food source

27. Free-Radical Damage and Antioxidant Protection

28. Vitamin E – Snapshot

29. Vitamin K • Roles • Blood clotting • Bone proteins • Deficiency • Toxicity • Jaundice • Requirements • Sources

30. Vitamin K – Snapshot

31. The Water-Soluble Vitamins • Dissolve in water • Absorption • Transport • Excretion • Sources • Food • Supplements

32. Vitamin C • Roles • Connective tissues • Collagen • Antioxidant • Protects iron • Prooxidant • Deficiency symptoms • Scurvy

33. Scurvy Symptoms – Gums and Skin

34. Vitamin C • Toxicity • Safe doses • Recommendations • Tobacco use • Physical stressors • Food sources • Destruction of vitamin C

35. Vitamin C – Snapshot

36. The B Vitamins in Unison • Function as part of coenzymes • Combines with enzyme to activate it • Coenzyme shape • Roles in metabolism • Help the body use the energy-yielding nutrients for energy • Cell multiplication

37. Coenzyme Action

38. Some Roles of the B Vitamins in Metabolism: Examples

39. The B Vitamins in Unison • Deficiencies • Every cell is affected • Symptoms • Rarely are isolated deficiencies

40. Thiamin • Energy metabolism of all cells • Nerve cell membranes • Deficiency • Beriberi • Alcohol abuse • DRI recommendation • Food sources

41. Thiamin Snapshot

42. Riboflavin • Role in energy metabolism of all cells • Deficiencies • Examples • Destruction of vitamin • UV light • Irradiation • Heat

43. Riboflavin Snapshot

44. Niacin • Participates in energy metabolism • Deficiency • Pellagra • Toxicity • Physician administration • “Niacin flush”

45. Niacin Snapshot

46. Folate • Helps synthesize DNA • Normal metabolism of several amino acids • Deficiency • Causes • Outcomes of deficiency • Anemia, diminished Immunity, abnormal digestive function • Cancer risk • Interaction with medications

47. Folate • Birth defects • Neural tube defects (NTD) • Toxicity • UL • Recommendations • Food sources of folate • Destruction of folate

48. Incidence of a Common NTD, Spina Bifida, Over Time

49. Folate Snapshot

50. Vitamin B12 • Closely related to folate • Helps maintain sheaths around nerve fibers • Deficiency • May be masked by folic acid intake • Pernicious anemia • Vitamin B12 absorption • Intrinsic factor • Food sources