Vitamins

1. Vitamins

2. Vitamins: Recall from the first week: Organic molecules (contain C, H, O, + other atoms) which regulate & assist with many metabolic reactions Micronutrients: Needed in only small amounts Found in all food groups

3. Vitamins:

4. Vitamins: Vitamins in foods: Many vitamins lost during long-term storage cooking Often enriched or fortified in foods Enriched—replacing lost ingredients Fortified—adding extra nutrients to foods May be obtained as “provitamins” – precursors which the body can convert to the active forms

5. Two groups: Fat-soluble Water-soluble Vitamins:

6. Two groups: Fat-soluble: Vitamins A, D, E, K Absorbed with fat into lymphatic system Stored in larger quantities Less vulnerable to cooking losses Vitamins:

7. Two groups: Fat-soluble: Vitamins A, D, E, K Absorbed with fat into lymphatic system Stored in larger quantities Less vulnerable to cooking losses Vitamins: • Water-soluble: Eight B vitamins and vitamin C • Absorbed into bloodstream • Stored in small amounts • More vulnerable to cooking losses

8. Vitamins: Let’s discuss the thirteen different vitamins, focussing on - Functions of each vitamin - Sources of each vitamin - Results of too little or too much of the vitamin Let’s start with Vitamin A

9. Vitamin A: Group of related molecules: Active forms (Retinoids) Retinol Retinal Retinoic Acid Provitamins (Carotenoids) Alpha-carotene Beta-carotene Gamma-carotene Stored in liver, released into blood as needed

10. Vitamin A: Retinoids are part of rhodopsin and iodopsin, the molecules which react to light in cells of the retina. Functions of vitamin A: 1. Vision – both night vision and color vision

11. Vitamin A: Functions of vitamin A: 2. Cell growth and differentiation Helps regulate protein synthesis as cells divide & differentiate, particularly in the skeletal system and skin.

12. Vitamin A: Functions of vitamin A: 3. Immune system Helps regulate the production and function of immune cells such as lymphocytes and macrophages.

13. Vitamin A: Functions of vitamin A: 4. Reproductive system Helps regulates sperm production and the function of uterus, Fallopian tubes, and vas deferens. Required for normal development of embryo and fetus.

14. Vitamin A: Dietary sources of vitamin A: Retinoids are only found in foods of animal origin: liver, eggs, milk Carotenoids (can be converted to retinoids) found in yellow / orange vegetables, some leafy green vegetables Both are often used to fortify cereals

15. Vitamin A: Dietary Recommendations: “Vitamin A” is actually a group of related molecules which can be converted into other forms, and the recommended intakes are different for each. Thus, Dietary Reference Intakes are expressed according to how active they are relative to the most common one, retinol. For adults, the Recommended Dietary Allowance of vitamin A is between 700 and 900 ug of retinol or its equivalent per day.

16. Vitamin A: Dietary Recommendations: Because vitamin A compounds are stored in the liver, excess dietary intake is not easily removed from the body and excess amounts can be toxic. Its Tolerable Upper Intake Level is about 3,000 ug of retinol or its equivalent per day.

17. Vitamin A: Deficiency: Blindness Dry, thick skin Reduced immunity Groups at risk Elderly Premature infants Alcohol or liver disease Absorption problems

18. Vitamin A: Excess: Dry, itchy skin Fingernail and hair damage Brittle bones Liver damage Muscle damage Anemia In pregnancy it is a teratogen – a substance which causes birth defects

19. Vitamin D: Next: Vitamin D “Vitamin D” is also a group of related compounds.

20. Vitamin D: Next: Vitamin D “Vitamin D” is also a group of related compounds. The two most common and important are ergocalciferol (also known as D2) and cholecalciferol (D3). These are converted in the liver and kidneys to the active form of the vitamin 25-hydroxyvitamin D [25(OH)D], also known as calcitriol.

21. Regulates blood calcium levels in three ways: Vitamin D: Function of vitamin D:

22. Regulates blood calcium levels in three ways: Vitamin D: Function of vitamin D:

23. Regulates blood calcium levels in three ways: Vitamin D: Function of vitamin D:

24. Dietary sources of vitamin D: Sun exposure Oily fish (e.g. sardines, herring, salmon Most of our intake is from fortified foods such as milk and cereal Vitamin D:

25. Dietary Recommendations: In the absence of sunlight exposure, the Adequate Intake of vitamin D is 5 to 10 ug/day. However, most people are exposed to enough sunlight for their skin to produce at least some of this: Light-skinned individuals: 8 to 30 minutes per week Dark-skinned individuals: 20 to 90 minutes per week Vitamin D:

26. Dietary Recommendations: Like vitamin A, vitamin D is stored in the liver, so excess dietary intake is not easily removed from the body and excess amounts can be toxic. Tolerable Upper Intake Level for most people: 50 ug/day Vitamin D:

27. Deficiency results in insufficient blood calcium levels Rickets in children Osteomalacia and osteoporosis in adults Vitamin D:

28. Deficiency results in insufficient blood calcium levels Rickets in children Osteomalacia and osteoporosis in adults Vitamin D: Excess: Hypercalcemia leading to: Failure of nerve conduction Muscle weakness / fatigue Digestive / absorption problems Kidney stones / tissue calcification Excessive thirst and urination Confusion / lethargy Severe: heart and breathing stop

29. Vitamin E: Next: Let’s move on to Vitamin E “Vitamin E” is also a group of related compounds: - alpha-tocopherol - beta-tocopherol - gamma-tocopherol - delta-tocopherol - alpha-tocotrienol - beta-tocotrienol - gamma-tocotrienol - delta-tocotrienol

30. Vitamin E: Next: Let’s move on to Vitamin E “Vitamin E” is also a group of related compounds: - alpha-tocopherol - beta-tocopherol - gamma-tocopherol - delta-tocopherol - alpha-tocotrienol - beta-tocotrienol - gamma-tocotrienol - delta-tocotrienol All are active and have similar effects. but alpha-tocopherol is the most common

31. Vitamin E: Function of vitamin E: All forms of the vitamin are antioxidants: They react with, and thus neutralize, highly reactive products of metabolism called oxygen free radicals in cell membranes of the heart, lungs, nerves, eyes, and other tissues. They also appear to protect against DNA mutations and to help regulate cellular growth and differentiation.

32. Vitamin E: Dietary sources of vitamin E: • Nuts • Seeds • Corn • Avocados • Tomatos • Leafy vegetables • Vegetable oils • Wheat germ oil Most of our intake is from fortified foods such as cereal and milk

33. Vitamin E: Dietary Recommendations: Recommended Dietary Allowance = 15 mg/day Tolerable Upper Intake Level = 800 to 1000 mg/day

34. Vitamin E: Deficiency: Very rare, take years to develop Nervous disorders: - Motor weakness - Sensory problems - Speech problems - Cataracts Slow growth Slow healing

35. Vitamin E: Excess: Very rare Abnormal blood clotting Abnormal immune function

36. Vitamin K: The last of the fat-soluble vitamins: Vitamin K Just like vitamins A, D, and E, “Vitamin K” is a group of related compounds rather than a single molecule. These are the phylloquinones and menaquinones.

37. Vitamin K: Function of vitamin K: Vitamin K regulates the reactions of blood clotting It helps regulate bone growth

38. Vitamin K: Dietary sources of vitamin K: • Leafy vegetables • Blueberries and blackberries • Legumes (beans, peas, etc.) Bacteria in the large intestine synthesize and release Vitamin K, which can then be absorbed

39. Vitamin K: Dietary Recommendations: Adequate intake = 90 ug/day for women = 120 ug/day for men Because the liver easily breaks down vitamin K, no Tolerable Upper Intake Level has been established

40. Vitamin K: Deficiency: Rare except in people with malabsorption syndromes or taking antibiotics which kill intestinal bacteria Infants often given supplemental vitamin K Abnormal clotting, internal bleeding

41. Vitamin K: Excess: Very rare No symptoms defined

42. Vitamins: Vitamins A, D, E, and K were “fat soluble”, stored in the liver or fat cells. Vitamin C and the eight B vitamins are “water soluble”, distributed through the fluids of the body and eliminated by the kidneys.

43. Vitamin C: Let’s start discussing the water-soluble vitamins with Vitamin C Also called “ascorbate” or “ascorbic acid”

44. Vitamin C: Function of vitamin C: It is an antioxidant which reacts with, and thus neutralizes, highly reactive products of metabolism called oxygen free radicals in the cells of many tissues and organs. Cells also need vitamin C to produce the protein collagen which holds them together and forms many of the body’s connective tissues. It helps synthesize a number of different hormones and neurotransmitters and helps regulate the immune system.

45. Vitamin C: Dietary sources of vitamin C:

46. Vitamin C: Dietary Recommendations: Recommended Dietary Allowance = 90 mg/day for men = 75 mg/day for women (more if pregnant or breastfeeding) Tolerable Upper Intake Level = 1,800 to 2,000 mg/day

47. Vitamin C: Deficiency: Scurvy: Bone and joint deterioration Connective tissues weaken Gums bleed Skin hemorrhages Open wounds Can be fatal

48. Vitamin C: Excess: Removed through the urine, but megadoses can cause Abdominal cramping & diarrhea Kidney stones Liver damage

49. B Vitamins: When the B vitamins were first discovered, they were thought to be just a single compound which acted as a “coenzyme” – a molecule which binds to enzymes and is necessary for them to function.

50. B Vitamins: When the B vitamins were first discovered, they were thought to be just a single compound which acted as a “coenzyme” – a molecule which binds to enzymes and is necessary for them to function. Fairly soon, however, eight different molecules were identified with specific functions. These were identified by adding numbers to the “B” designation.