Chapter 9: The Fat-Soluble Vitamins

1. Chapter 9: The Fat-Soluble Vitamins

2. Vitamins Definitions • Organic compound found in foods, noncaloric • Required in small amounts • Required in the diet (essential) • Proven to be required for health, growth, and reproduction ; deficiency syndrome identified • There are 4 fat soluble vitamins & • 9 water soluble vitamins for a total of 13. • Your text also lists choline with the water soluble vitamins although it is not considered a vitamin since there is no known deficiency disease

3. FAT Soluble VitaminsADEK • Stored in tissues in larger quantities • Soluble in lipids • Not readily excreted; • High long term intakes can cause toxicity • Less vulnerable to cooking losses • Absorbed along with fat • Transported like fat in chylomicrons, VLDL, LDL • Deficiencies due to fat mal-absorption or very low fat diets or liver and pancreas disorders

4. Vitamin Absorption

5. Pro-Vitamins • Precursors of vitamins • Are converted into the active vitamin form • E. g. beta-carotene converted into vitamin A

6. Sources of Vitamin A • Chemical names: • 3 forms: retinol, retinal, retinoic acid • Active forms: Preformed • Retinoids (retinal, retinol, retinoic acid) • In animal products: beef liver, fish, fish oils, eggs, • Pro-forms • Carotenoids (beta-carotene, alpha carotene,lutien, lycopene, zeaxanthin) • Must be converted to retinoid form • Found in plant products: carrots, spinach, sweet potatoes, broccoli, romaine lettuce, mangoes, peaches

7. Functions of Vitamin A • Major use is in cell growth and differentiation • Attaches nuclear retinoid acid receptor (RAR) & retinoic X receptor (RXR) • Important for embryo development, gene expression • Associated with improved immune system

8. Functions of Vitamin A • Promotes proper fetal growth at proper times • Acts as a morphogen • substances believed to be present in the growing embryo, controlling its growth pattern. • variations in the concentration of morphogens in different parts of the embryo cause them to grow at different rates. • Synthesis of bone protein and enlargement of bone • Production of mucus • Promotes synthesis of keratin proteins • Skin, hair, nails

9. Functions of Vitamin A • Vision: Retina • Cones vision in bright lights • Rods vision in dim light • Retinal combines with opsin to form Rhodopsin = light capturing pigment • Carotenoids act as antioxidants • Lower risk of breast cancer with vitamin A supplements

10. Deficiency of Vitamin A • Night blindness • Decreased mucus production • Leading to bacterial invasion in the eye and Xerophthalmia- dryness of cornea & eye membranes: read pg 298 • Conjunctival xerosis • Bitot’s spots • Irreversible blindness amy result • Follicular hyperkeratosis • the excessive development or retention of keratin by the epidermis. • Bumpy, rough, and dry skin, hair follicles become plugged

11. RDA for Vitamin A for Adults • Units = Retinol Activity Equivalents • 1 RAE = 1 ug (1/1 000 000 g) • 900 REA for men (3000 REA max) • 700 REA for women (Max: 3000 RAE) • Average intake meets RDA • Much stored in the liver • Vitamin A supplements are unnecessary • No separate RDA for carotenoids

12. Effect of Vitamin A

13. Hypervitaminosis A: Toxicity of Vitamin A Acute toxicity • Ingestion of LARGE dose(s) of vitamin A (within a short period) • Causes intestinal upset, headache, blurred vision, muscular incoordination, dizziness, death by convulsions • Chronic • Large intake of vitamin A over a long period (10X RDA) • Bone/muscle pain, loss of appetite, skin disorders, headache, dry skin, hair loss, increased liver size, vomiting; dry itchy & flaky skin, fructures

14. Hypervitaminosis A: Toxicity of Vitamin A Teratogenic • Produce physical defect on developing fetus • Spontaneous abortion, birth defects • May occur with as little as 3 x RDA of preformed vitamin A Upper Level for Vitamin A • 3000ug for adults Fatal dose -12 g of vitamin A can be fatal

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

16. Vitamin D: sources • Sun exposure to skin • Synthesized from cholesterol- cholecalciferol • Classified as a prohormone • Diet • Fortified milk & cereal

17. Vitamin D Synthesis

18. Vitamin D synthesis • Liver hydroxylase • Catalyzed conversion formation of provitamin D: 25-OH vitamin D • Kidney: Kidney hydroxylase • produces 1,25 dihydroxycholecalciferol (1,25 vit D) • Also called Calcitrol; active hormone form • Kidney main site of vit D formation

19. Functions of Vitamin D • Regulates blood Ca levels • Increase absorption of Ca and P • Changes resorption of Ca and P in kidneys • Causes Ca & P to deposit in bone • Strengthens bone-bone mineralization • Causes differentiation of osteoclast into osteoblasts for new bone formation • Maintains function of neuromuscular junctions • Reduces cancer cell proliferation by inducing differentiation

20. Vitamin D • Deficieny • Rickets in children • Osteomalacia (soft bone) and osteoporosis in adults • Toxicity • Hypercalcemia

21. 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 ~6 months of age. The Adequate Intake (AI) for Vitamin D

22. Vitamin D as a Medicine Type II (age-related) osteoporosis • Loss of bone mass due to limited ability to absorb vitamin D or produce calcitriol • 10-20 ug vitamin D/ day plus calcium decrease bone fracture • Risk for hypercalcemia Psoriasis • Skin disorder • Topical treatment

23. Toxicity Warning • Occurs at 5-10x the AI • Upper level is 50ug/d • Result from excess supplementation (not from sun exposure or milk consumption) • Sign and symptoms: • Over absorption of calcium (hypercalcemia), increase calcium excretion • Soft tissue calcification • Calcium deposits in kidneys, heart, and blood vessels • Mental retardation in infants • Renal lethiasis (Ca stones )

24. Vitamin E: Functions • Refers to a family of compounds called • Tocopherols and tocotrienols • Antioxidant; donates electron to oxidizing agent • Prevents increase in free radicals • Protect 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

25. Functions • Examples of free radicals • Peroxyl-radical-a lipid radical from breaking of FA chains, has an unpaired electron • Reactive oxygen species (ROS) from chemical pathways that make ATP

26. Functions • May prevent oxidation of Vitamin A • May have a role in the synthesis of Hemoglobin or • May activate enzymes in the mitochondria to improve O2 utilization

27. Other antioxidants • Glutathione peroxidase • Superoxide dismutase • Catalase

28. Food Sources of Vitamin E • Plant oils • Wheat germ • Asparagus • Peanuts, nuts & seeds • Margarine, shortenings, salad dressing, oils • Nuts and seeds • Actual amount is dependent on harvesting, processing, storage and cooking

29. RDA for Vitamin E • 15 mg/day for women and men • Recommendation prevents hemolysis of RBC

30. Deficiency of Vitamin E • Hemolytic anemia, why? • Peripheral neuropathy-damage to nerve cells • Insufficient bile production • May contribute to heart disease, cancer, premature aging and decreased fertility • Rare

31. Toxicity of Vitamin E • Supplements up to 800 IU is probably harmless • Upper Level is 1,000 mg/day of any form of supplementary alpha-tocopherol • Upper Level is 1500 IU (natural sources) or 1100 IU (synthetic forms) • Inhibit vitamin K metabolism and anticoagulants

32. SUPPLEMENTATION: • One study by Kobyoshi found that 1200 IU daily for 6 weeks in non-athletes: • Improved max VO2 • Reduced Blood Lactic Acid during submaximal exercise • Increased aerobic endurance at altitudes between 5,000 and 15,000 feet. • Theory was to prevent oxidation of RBC membranes that might occur at altitude • Research needed on athletes • May improve endurance in athletes exercising in high-smog areas. • Athletes should take between 100-200 IU per day, however there is a lack of conclusive evidence of a beneficial effect.

33. Vitamin K (“Koagulation”) • Phylloquinone (K1) and menaquinones (K2) • Classified as • Fat soluble • Blood Coagulation Vitamin or • Anti-hemorrhagic Vitamin • Menaquinones are synthesized by the bacteria in the colon and are absorbed

34. Function of Vitamin K • Formation of Four compounds essential to two steps of blood clotting • Enhances function of OSTEOCALCIN, a protein with an important role in strengthening bones • Calcium-binding potential

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

36. Vitamin K Deficiency • Impares blood clotting and leads to hemorrhage • May effect Kidney excretion of Calcium and may be involved in osteroporosis. • Rare, however may occur due to antibiotic medications that kill intestinal bacteria

37. Food Sources of Vitamin K • Liver • Egg yolk • Milk • Green leafy vegetables • Broccoli • Peas • Green beans

38. Adequate Intake for Vitamin K • 90 ug/day for women • 120 ug/day for men • RDA met by most • Excess vitamins A and E interferes with vitamin K • Newborns are injected with vitamin K(breast milk is a poor source) • Toxicity unlikely; readily excreted

39. SUPPLEMENTATION: • No supplementation studies • No evidence that supplementationwould improve health status or athletic performance. • Supplements only available by prescription

40. Water Soluble Vitamins • NINE WATER SOLUBLE VITAMINS • B-complex: • B1 Thiamin • B2 Riboflavin • B6 Pyridoxine, pyridoxal, pyridoxanine • B12 Cobalamin, cyanocobalamin • Niacin • Biotin • Folic Acid • Pantothenic Acid • C Ascorbic Acid

41. THIAMIN (VITAMIN B1) • RDA: • Adult males, 1.5 mg/day • Adult females, 1.1 mg/day • SOURCES: • Whole grain cereals • Beans • Seeds, Nuts • Pork • Fruits and Vegetables • Limited synthesis by bacteria in intestine

42. Functions • Central role in the metabolism of Glucose • Part of the coenzyme thiamine pyrophosphate needed to convert pyruvate to acetyl CoA for entrance into the Krebs Cycle • Normal functioning of the Nervous System • Energy derivation from glycogen in the muscles

43. DEFICIENCY • Symptoms occur in several weeks • 1. loss of appetite • 2. mental confusion • 3. muscular weakness • 4. pain in calf muscles • 5. prolonged deficiencies lead to Beriberi – damage to nervous system and heart • Rare, but more common in alcoholics, homeless, and other special groups • Exercise and high carbohydrate intake increases need for Thiamin

44. SUPPLEMENTATION: • No ergogenic effect (Increase in muscular work capacity) if taken beyond RDA • Japanese research showed fewer subjective complaints of fatigue following strenuous exercise with thiamin supplementation • Megadoses up to 1000 mg showed no adverse effect.

45. RIBOFLAVIN (VITAMIN B2) • RDA: • Adult male, 1.7 mg/day • Adult female, 1.3 mg/day • SOURCES: • Milk and Dairy Products • Liver • Eggs • Dark-green Leafy Vegetables • Wheat Germ • Yeast • Whole-grain products • Enriched breads and cereals

46. METABOLIC FUNCTION: • Formation of several oxidative enzymes known as flavoproteins • Flavoproteins involved in energy production from Carbohydrate and Fats in the body cells • Involved in Protein metabolism • Maintenance of healthy skin

47. DEFICIENCY: • Glossitis – inflammation of tongue • Cracks at the corners of the mouth • Dry, scaly skin at corners of the nose • SUPPLEMENTATION: • Untrained women initiating an aerobics program may need higher intake of Riboflavin to synthesize more flavoproteins; Early stages of training need about 1.1 mg/1000 kcal • Research shows no ergogenic effect • Megadoses offer no adverse effects

48. NIACIN • RDA: • Adult Males, 19 NE (Niacin equivalents) • Adult Females, 15 NE • About 6.6 mg/1000 kcal intake • 1 NE = 1 mg of Niacin or 60 mg of Tryptophan • Excess Tryptophan is converted to Niacin

49. SOURCES: • Lean Meats • Organ Meats • Fish • Poultry • Whole-grain cereal products • Legumes, such as beans and peanuts • Enriched foods • From Excess Tryptophan from Milk and eggs

50. METABOLIC FUNCTION: • Serves as a component of a coenzyme that is important in glycolysis • Serves as a component of a coenzyme that is important in Fat metabolism