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Vitamins

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A brief class for undergraduates

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Vitamins

  1. 1. Vitamins DR HARSIMRAT SINGH WARAICH M.D
  2. 2. What are vitamins  Complex substances that regulate body processes  Coenzymes (partners) with enzymes in reactions  No calories, thus no energy
  3. 3. Naming Vitamins  Each new vitamin is temporarily named when discovered  The naming of vitamins follows the letters of the alphabet, starting with A; up to the letter K  A, B, C, D, E, and K  B has many subscripts  F, G, and H were dropped
  4. 4. Criteria for Vitamins  Cannot be synthesized in ample amounts in the body  Chronic deficiency is likely to cause physical symptoms  Symptoms will disappear once the vitamin level in the body is restored  Deficiency can cause permanent damage
  5. 5. Categories Fat-solubleFat-soluble Dissolve in fatDissolve in fat Can be storedCan be stored Water-solubleWater-soluble Dissolve in waterDissolve in water Carried inCarried in bloodstream, notbloodstream, not storedstored A, D, E, KA, D, E, K C and B-complexC and B-complex vitaminsvitamins A and D excess can beA and D excess can be harmfulharmful Excess amounts mayExcess amounts may cause extra work oncause extra work on kidneyskidneys
  6. 6. Classification of Vitamins FAT SOLUBLE A D E K  B1- Thiamine  B2 - Riboflavin  B3 – Niacin  B5 – pantothenic acid  B6 –Pyridoxine  B8 – biotin  B 9-Folic acid  B12 -Cyanocobalamin  Vitamin C (ascorbic acid) 6 WATER SOLUBLE
  7. 7. Vitamin Absorption and Storage  All absorption takes place in the small intestine  Fat-soluble vitamins  Are absorbed in the duodenum  Storage  Vitamin A is mainly stored in the liver  Vitamins K and E are partially stored in the liver  Vitamin D is mainly stored in the fat and muscle tissue
  8. 8. The Location of Vitamin Absorption Preferentially absorbed in jejunum Folate (Jejunum only) Vitamin B12 (Ileum Colon Thiamin Riboflavin Niacin Biotin
  9. 9. Vitamin A (and carotenoids)  Functions:  Normal vision  Protects from infections  Regulates immune system  Antioxidant (carotenoids)  Food sources:Food sources:  Liver  Fish oil  Eggs  Fortified milk or other foods  Red, yellow, orange, and dark green veggies (carotenoids)
  10. 10. Causes of Vitamin A Deficiency  Inadequate intake (strict vegetarian diet)  Fat malabsorption  Crohn's ileitis  Pancreatic insufficiency  Cystic fibrosis  Cholestatic liver disease  Severely limited protein intake
  11. 11. Vitamin A Deficiency Clinical Manifestations 1. Night blindness 2. Bitot's spots - Abnormal squamous cell proliferation and keratinization of the conjunctiva - Xerophthalmia: abnormal dryness of the conjunctiva and cornea of the eye 3. Irreversible eye conditions: -Xerosis -Corneal perforation -Keratomalacia -Punctate keratopathy
  12. 12. Vitamin D (the sunshine vitamin)  Functions:  Promotes absorption of calcium and phosphorus  Helps deposit those in bones/teeth  Regulates cell growth  Plays role in immunity  Sources:  Sunlight (10 – 15 mins 2x a week)  Salmon with bones  Milk  Orange juice (fortified)  Fortified cereals
  13. 13. Findings in Vitamin D Deficiency  ↓ intestinal absorption of calcium and phosphorus  Hypocalcemia  Hypophosphatemia  Phosphaturia  Secondary hyperparathyroidism (bone  Demineralization of bones  Osteoporosis/ostoemalacia in adults adults  Rickets in children  Muscle pain/weakness
  14. 14. Vitamin E  Functions:  Antioxidant, may lower risk for heart disease and stroke, some types of cancers  Sources:  Vegetable oils  Foods made from oil  Nuts  Seeds  Wheat germ  Green, leafy vegetables
  15. 15. Vitamin E Deficiency  Vitamin E deficiency is uncommon due to the abundance of tocopherols in our diet  Divided to:  Subclinical (low serum tocopherol level)  Clinical Neuromuscular disorders Hemolysis
  16. 16. Vitamin K  Functions:  Helps in blood clotting  Helps body make some other proteins  Sources:  Body can produce on its own (from bacteria in intestines)  Green, leafy veggies  Some fruits, other veggies, and nuts
  17. 17. Water Soluble Vitamins  B1, thiamine  B2, riboflavin  B6, pyridoxamine  B12  Biotin  Panothenic acid  Niacin  Folic acid  Vitamin C 17
  18. 18. Thiamin (B1) Functions:  Helps produce energy from carbohydrates Sources: Whole- grain and enriched grain products Pork Liver
  19. 19. Individuals at Risk for Thiamine Deficiency  Alcoholics  Calorie-protein poor diet  Severe malnutrition  Malabsorption  Gastric bypass  Chronic renal failure  Prolonged febrile illness
  20. 20. Thiamine Deficiency  Beriberi  Wernicke-Korsakoff syndrome  Leigh's syndrome
  21. 21. Riboflavin (B2)  Functions:  Involved in cellular metabolism, oxidation - reduction reactions; electron transporter  Essential component of coenzymes  flavin mononucleotide (FMN)  flavin-adenine dinucleotide (FAD)  Sources:  Liver  Yogurt and milk  Enriched grains  Eggs  Green, leafy veggies
  22. 22. Patients at Risk for Vit. B2 Deficiency  Avoidance of dairy products  lactose intolerance  Anorexia nervosa  Malabsorptive syndromes  Celiac sprue  Malignancies  Short bowel syndrome  Inborn errors of metabolism  defect in riboflavin synthesis
  23. 23. NIACIN (Vitamin B3) Forms  Nicotinic acid  Nicotinamide Functions: • Component of NAD/NADP - essential for redox reactions and hydrogen transport, metabolism of carbohydrates, fatty acids, and proteins Dietary sources:  Meats (liver), milk, fish, whole-grain, nuts
  24. 24. Niacin (B3) Deficiency  Defective metabolism  Disease – pellagra – The Four D’s  Dermatitis  Diarrhea  Dementia  Death 24
  25. 25. Pyridoxine (B6)  Functions:  Transamination and decarboxylation of AA  Gluconeogenesis  Formation of niacin/serotonin from tryptophan  Steroid hormone modulation  Sources:  Chicken  Fish  Pork  Liver  Whole grains  Nuts  Legumes
  26. 26. Vitamin B6 Deficiency  Overt deficiencies are rare  Manifestations  Stomatitis, glossitis, cheilosis  Seborrheic dermatitis  Irritability, confusion, depression  Sideroblastic anemia
  27. 27. Folate (Folic acid)  Functions:  Produces DNA and RNA, making new body cells  May protect against heart disease  Lowers risk of neural tube defects in fetus  Controls plasma homocysteine levels (related to heart disease)  Sources:  Fortified and enriched grains  Legumes  Green, leafy veggies  Peanuts
  28. 28. Causes of Folate Deficiency Nutritional deficiency Poor dietary intake Alcoholism Elderly (10% in pts >75 years) Malabsorption Sprue IBD Gastric bypass
  29. 29. Vitamin B12 (cobalamin)  Functions:  Works with folate to make RBC’s  Helps body use fatty acids/amino acids  Sources:  Animal products  Meat  Fish  Poultry  Eggs  Milk, other dairy
  30. 30. Biotin (Vit. B7)  Functions:  Produces energy  Helps body use proteins, carbs, and fats from foods  Sources:  Eggs  Liver  Wheat germ  Peanuts  Cottage cheese  Whole grain bread
  31. 31. Pantothenic Acid (Vit B5)  Functions  Helps produce energy by helping the body use proteins, fat, and carbohydrates from food  Sources:  Found in almost all foods  Meat, poultry, fish  Whole grain cereals  Legumes  Milk  Fruits, veggies
  32. 32. Vitamin C  Functions:  Helps produce collagen (connective tissue in bones, muscles)  Keeps capillary walls, blood vessels firm  Helps body absorb iron and folate  Heals cuts and wounds  Protects from infection, boosts immunity  Antioxidant  Sources  Citrus fruits  Other fruits, veggies
  33. 33. Symptoms of Vitamin C Deficiency  Swollen and bleeding gums  Loosened teeth  Arthralgias and joint effusions  Lower extremities weakness  Petechial hemorrhage  Ecchymosis  Slow wound healing  Anemia   Death
  34. 34. Conclusions Diagnosis of deficiency can be difficult History is a key to diagnosis of vitamin deficiency Blood tests are important in diagnosis The majority of patients with unclear diagnosis should receive vitamin supplementation
  35. 35. Thank You

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