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Fat-Soluble Vitamins

Fat-Soluble Vitamins. Chapter 12. Learning Outcomes. Define the word vitamin and list 3 characteristics of vitamins as a group Classify the vitamins according to whether they are fat or water-soluble List 3 important food sources for each fat- soluble vitamin

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Fat-Soluble Vitamins

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  1. Fat-Soluble Vitamins Chapter 12

  2. Learning Outcomes • Define the word vitamin and list 3 characteristics of vitamins as a group • Classify the vitamins according to whether they are fat or water-soluble • List 3 important food sources for each fat- soluble vitamin • List the major functions for each fat-soluble vitamin

  3. Learning Outcomes • Describe the deficiency symptoms for each fat-soluble vitamin and state the conditions in which deficiencies are likely to occur • Describe the toxicity symptoms caused by excess consumption of certain fat-soluble vitamins • Evaluate the use of vitamin and mineral supplements with respect to their potential benefits and risks to health

  4. Vitamins: Essential Dietary Components • Two categories • Fat-soluble: Vitamins A, D, E and K • Water-soluble: Vitamin B complex (8) and C • Compare and Contrast • Absorption of vitamins • Malabsorption of vitamins • Transport of vitamins • Storage of vitamins in the body

  5. Vitamin A • Retinoids • Active form: preformed Vitamin A • Retinal, retinol and retinoic acid • Dietary sources: liver, fish oils, fortified dairy products and eggs • Caroteinoids • Provitamins-can be converted to Vitamin A • Dietary sources: dark green and yellow orange vegetables and fruits

  6. Equivalents • Used for some vitamins when there are multiple forms of the vitamin so there is one common unit

  7. Vitamin A Needs • RDA • Men • 900 micrograms retinol activity equivalent (RAE) • Women • 700 micrograms RAE • Daily Value (used on packaging) • Approximately 1,000 micrograms • Average current intake meets DRI

  8. Which are vitamin A and which are beta carotene?

  9. Absorption, Transport and Excretion of Vitamin A • Absorption • Packaged with chylomicrons and transported via the lymphatic system • Transport • Retinoids-bound to retinol binding protein • Carotenoids-carried by VLDL • Excretion • Small amount in urine

  10. Functions of Vitamin A (Retinoids) • Growth and Development • Embryonic development • Epithelial cells and mucus production in lungs, trachea, skin, GI tract • Immune Function • Maintains the ephithelium • Increased infections w/vit A deficiency • Dermatology • Topical and oral medications

  11. Functions of Vitamin A (Retinoids)

  12. Functions of Vitamin A (Retinoids)

  13. Functions of Carotenoids • Provitamin A activity • Beta carotene (most Vitamin A activity of the carotenoids) • NOT toxic • Other health benefits • Cataracts • Lung cancer • Macular degeneration • Other carotenoids • Lutein and zeaxanthin • Lycopene

  14. Vitamin A Diseases • Deficiencies • Night blindness • Xerophthalmia (permanent blindness) • Follicular hyperkeratosis • Impaired growth • Increased infections • Increased transmission of maternal/fetal HIV

  15. Vitamin A Diseases • Toxicities • Hypervitaminosis A • Upper limit-3000 micrograms/day retinol (not carotenoids) • Appears w/ chronic supplement use at 5-10x the RDA • Acute (100x RDA for a few days) • GI upset, headache, poor muscle coordination • Chronic (chronic use of 10x RDA) • Joint pain, liver damage, coma, death • Teratogenic

  16. Vitamin D • “Conditional” or prohormone • Requirement-sunlight 2-3 times a week for 10-15 minutes • Skin formation: • In skin, sunlight (UV light) changes 7-dehydrocholesterol (made from cholesterol) to vitamin D3 • Whether it is made in the skin or ingested, D3 is converted to form 25-hydroxycholecalciferol or 25(OH)D) in the liver. Once made, the product is released into the plasma, where it binds to vitamin D binding protein. • 25(OH)D travels to liver and kidney and converted to bio active form-1,25(OH)2D (ligand for VDR, responsible for most actions of vitamin D)

  17. Vitamin D Needs • The new reference intakes (RDA) for vitamin D are based on amount need to maintain serum 25-hydroxyvitamin D level of 20 ng/mL (for optimal bone and overall health): • 1–70 years of age: 600 IU/day (15 μg equivalent) • 71+ years of age: 800 IU/day • Recommendations assumes no skin synthesis of vitamin D and refers to total intake from food, beverages and supplements.

  18. Absorption, Transport and Excretion of Vitamin D • Absorption and Transportation • Absorbed via micelles and transported via chylomicrons in the lymphatic system • Bound to a protein • Synthesis of the active form is regulated by parathyroid hormone and kidneys • Excretion • Small amount in urine and bile

  19. Functions of Vitamin D • Calcium and Phosphorus Homeostasis • Aid in increasing absorption of calcium • Aid in releasing calcium from bone, if necessary • Bone Health • Immune Function (cold and flu) • Cancer (breast, colon, prostrate) • Heart disease • Type 1 diabetes

  20. Vitamin D Diseases • Deficiencies • Children-rickets • Adults-osteomalacia • Toxicities • Does not occur from sunlight or dietary sources • Does occur with supplementation • Upper limit • 4000 IU daily

  21. Vitamin E • 8 compounds • 4 tocopherols • 4 tocotrienols • Dietary sources: • Plant oils, wheat germ, asparagus, almonds, peanuts and sunflower seeds

  22. Vitamin E Needs • RDA • 15 mg daily of alpha-tocopherol • Daily Value • 30 IU (approximately 20 mg) • Adults consume approximately 2/3 the RDA

  23. Absorption, Transport and Excretion of Vitamin E • Absorption and Transportation • Micelles into chylomicrons • Transported via lipoproteins • Stored in adipose tissue • Excretion • Bile, urine and skin

  24. Vitamin E Functions • Antioxidant • Reduces oxidative stress • Other antioxidant compounds • Glutathione peroxidase • Selenium • Superoxide dismutase • Copper, Zinc and Manganese

  25. Vitamin E Diseases • Deficiencies • Hemolytic anemia-rare in humans • Toxicities • Interfere with Vitamin K and cause hemorrhaging • Upper limit: • 1000 mg natural sources • 1100 IU synthetic sources

  26. Vitamin K • Menaquinones • Synthesized by gut bacteria • Fish oils and meats • Phylloquinones • Plants: green leafy vegetables, broccoli, peas and green beans • Most biologically active

  27. Vitamin K Needs • AI • Women • 90 micrograms daily • Men • 120 micrograms daily • Daily Value • 80 micrograms

  28. Absorption, Transport and Excretion of Vitamin K • Absorption and Transportation • Absorbed in small intestine, via chylomicrons in lymphatic system. • Transported via lipoproteins and stored in the liver • Excretion • Primarily bile, small amount urine

  29. Vitamin K • Functions • Blood clotting factors • Bone health • May protect the body from inflammation • Deficiency • Rare: long term antibiotic use or fat malabsorption • Toxicity • No UL

  30. Dietary Supplements • Dietary Supplement Health and Education Act of 1994 (DSHEA) • A mineral • A vitamin • An amino acid • A herb, a botanical, or a plant extract • A combination of any of the above

  31. Vitamin/Mineral Supplementation • Individuals that may benefit • Things to look for: • No more than 100% Daily Value • USP certification • Diet and supplement shouldn’t exceed ULs • Check for superfluous ingredients

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