Vitamins

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Vitamins

  1. 1. VITAMINS BIOCHEM LEC WK 5
  2. 2. VITAMINS <ul><li>VITAMINS- essential organic molecules needed in very small amounts for cellular metabolism </li></ul><ul><li>Primary Deficiency of a Vitamin- occurs when the vitamin is not consumed in sufficient amounts to meet physiologic needs </li></ul><ul><li>Secondary Deficiency- develops when absorption is impaired or excess excretion occurs </li></ul>
  3. 3. VITAMINS <ul><li>Categories </li></ul><ul><li>Water Soluble Vitamins- Vitamin B Complex, Choline, Vitamin C </li></ul><ul><li>Fat Soluble Vitamins- Vitamins A, D, E, K </li></ul><ul><li>Food Sources: Almost all foods, yet NO one food group is a good source of all vitamins; fresh fruits and vegetables are particularly rich sources </li></ul>
  4. 4. WATER SOLUBLE VITAMINS <ul><li>THIAMINE (B1) </li></ul><ul><li>functions: to serve as coenzyme in energy metabolism; role in nerve functioning related to muscle actions </li></ul><ul><li>RDA: 1.2 mg for men/ 1.1 mg for women </li></ul><ul><li>Deficiency: BERI-BERI—2 Types </li></ul><ul><li>WET- manifests with edema affecting cardiac function </li></ul><ul><li>DRY- affects the CNS, producing paralysis and extreme muscle wasting </li></ul><ul><li>Toxicity: non-toxic; excess is excreted in urine </li></ul>
  5. 5. WATER SOLUBLE VITAMINS <ul><li>RIBOFLAVIN (B2) </li></ul><ul><li>function: coenzyme in the release of energy from nutrients </li></ul><ul><li>sensitive to light </li></ul><ul><li>RDA: 1.3 mg for men/ 1.1 mg for women </li></ul><ul><li>Deficiency: ARIBOFLAVINOSIS—S/SX </li></ul><ul><li>CHEILOSIS- lips become swollen and cracks develop in corners of the mouth </li></ul><ul><li>GLOSSITIS- inflammation of the tongue </li></ul>
  6. 6. WATER SOLUBLE VITAMINS <ul><li>NIACIN (B3) </li></ul><ul><li>functions: coenzyme for many enzymes; critical for glycolysis and Kreb’s cycle </li></ul><ul><li>occurs naturally in 2 forms: NICOTINIC ACID and NIACINAMIDE </li></ul><ul><li>RDA: 16 NE for men/ 14 NE for women </li></ul><ul><li>Deficiency: PELLAGRA—3D’s ( Diarrhea, Dermatitis, Dementia ) </li></ul>
  7. 7. WATER SOLUBLE VITAMINS <ul><li>PYRIDOXINE (B6) </li></ul><ul><li>functions: coenzyme in the metabolism of amino acids and CHON </li></ul><ul><li>3 forms ( pyridoxine, pyridoxal, pyridoxamine ) all can be converted to the coenzyme pyridoxal phosphate for use in the body </li></ul><ul><li>RDA: 1.3 mg for men and women </li></ul><ul><li>Deficiency: S/SX: dermatitis, altered nerve function, weakness </li></ul>
  8. 8. WATER SOLUBLE VITAMINS <ul><li>FOLATE </li></ul><ul><li>function: coenzyme in reactions involving the transfer of 1-Carbon units during metabolism </li></ul><ul><li>4 forms ( folate, folic acid, folacin and pteroylglutamic acid ) </li></ul><ul><li>for folate to be maintained for use in the body, Vitamin B12 must be available </li></ul><ul><li>folate has a role in proper formation of fetal neural tubes (brain and spinal cord development) </li></ul><ul><li>RDA: 400 mcg for men/women 600mcg for pregnant women </li></ul><ul><li>Deficiency: megaloblastic anemia—large RBC that cannot carry oxygen </li></ul>
  9. 9. WATER SOLUBLE VITAMINS <ul><li>COBALAMIN/CYANOCOBALAMIN (B12) </li></ul><ul><li>functions: coenzyme in nucleic acid metabolism; needed for maturation of RBC </li></ul><ul><li>absorption of Vitamin B12 relies on an intrinsic factor (IF) a substance produced by stomach mucosa </li></ul><ul><li>deficiency: Pernicious Anemia- inadequate RBC formation caused by lack of IF in the stomach </li></ul>
  10. 10. WATER SOLUBLE VITAMINS <ul><li>BIOTIN </li></ul><ul><li>function: coenzyme in synthesis of fat, glycogen and amino acids </li></ul><ul><li>deficiency: S/SX: scaly red skin rash, hair loss, loss of appetite, depression </li></ul>
  11. 11. WATER SOLUBLE VITAMINS <ul><li>PANTOTHENIC ACID </li></ul><ul><li>function: for metabolism of CHO, FATS and CHON </li></ul><ul><li>deficiency: do not occur in nature </li></ul><ul><li>CHOLINE </li></ul><ul><li>function: needed for synthesis of acetylcholine, a neurotransmitter, and lecithin( phospholipid) </li></ul><ul><li>deficiency: rare </li></ul>
  12. 12. WATER SOLUBLE VITAMINS <ul><li>ASCORBIC ACID ( VITAMIN C ) </li></ul><ul><li>functions: collagen synthesis and other CT; antioxidant; iron absorption; coenzyme </li></ul><ul><li>RDA: 90 mg for men/ 75 for women/ 125 mg for smokers </li></ul><ul><li>Deficiency: SCURVY: S/SX—inflammation of CT, gingivitis, muscle degeneration, bruising and hemorrhaging as the vascular system weakens </li></ul>
  13. 13. FAT SOLUBLE VITAMINS <ul><li>VITAMIN A </li></ul><ul><li>functions: component of visual pigments; needed for maintenance of epithelial tissues; antioxidant </li></ul><ul><li>RDA: 900 mcg RAE for men/ 700 mcg RAE for women </li></ul><ul><li>Deficiency: XEROPHTHALMIA—night blindness progressing to a hard, dry cornea (keratinization) resulting in complete blindness </li></ul>
  14. 14. FAT SOLUBLE VITAMINS <ul><li>VITAMIN D </li></ul><ul><li>function: aid in absorption and use of calcium and phosphorus; promotes bone growth </li></ul><ul><li>precursor: 7-dehydrocholesterol (found in the skin) </li></ul><ul><li>active form: 1,25- dihydrocholecalciferol </li></ul><ul><li>deficiency: RICKETS- a childhood disorder caused by Vitamin D or Calcium deficiency that leads to insufficient mineralization of bone and tooth matrix </li></ul>
  15. 15. FAT SOLUBLE VITAMINS <ul><li>VITAMIN E (TOCOPHEROLS) </li></ul><ul><li>function: antioxidant </li></ul><ul><li>RDA: 15 mg TE for men/women </li></ul><ul><li>Deficiency: rare </li></ul><ul><li>VITAMIN K </li></ul><ul><li>function: cofactor in the synthesis of blood clotting factors </li></ul><ul><li>deficiency: inhibits blood coagulation </li></ul>

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