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The Vitamins

The Vitamins. Classifying Vitamins. Fat Soluble Vitamins A D E K. Water Soluble Vitamins. Vitamin C B Vitamins: Thiamin -- Biotin Riboflavin -- Pantothenic acid Niacin B 6 Folate (folic acid) B 12. Water Soluble Vitamins. Digestion, Absorption, and Transport

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The Vitamins

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  1. The Vitamins

  2. Classifying Vitamins • Fat Soluble Vitamins • A • D • E • K

  3. Water Soluble Vitamins • Vitamin C • B Vitamins: • Thiamin -- Biotin • Riboflavin -- Pantothenic acid • Niacin • B6 • Folate (folic acid) • B12

  4. Water Soluble Vitamins • Digestion, Absorption, and Transport • No chemical digestion needed • Absorbed in the SI into the capillaries • Vitamin B12 must bind with a protein called the intrinsic factor (IF) in the stomach for absorption to occur in the SI • No carriers required for transport in the blood

  5. Water Soluble Vitamins • Storage and excretion • Travel freely in the blood • Cells take up water soluble vitamins as needed • Limited storage beyond tissue saturation • Excess excreted in the urine

  6. Water Soluble Vitamins • Deficiency is more common than toxicity for the water soluble vitamins • Why?? • Any toxicity is likely to be due to overuse of vitamin supplements, not food intake

  7. Water Soluble Vitamins • Other interesting information: • Many are destroyed by light, heat, or exposure to oxygen • Best to cook whole in a minimum amount of water • Why?? • Frozen vegetables are often higher in vitamin content than grocery store “fresh” veggies • Why??

  8. Fat Soluble Vitamins • Digestion, Absorption, and Transport • Bile needed to emulsify fat soluble vitamins • Form chylomicrons (along with long chain fatty acids and monoglycerides) • Chylomicrons are absorbed into the lacteals • Travel through lymph system  blood  liver • Many require protein carriers to be transported in the blood

  9. Fat Soluble Vitamins • Storage • Stored in liver and fatty tissue • Unlimited stores possible • Greater risk of toxicity than deficiency for fat soluble vitamins • Why??

  10. Fat Soluble Vitamins • Other interesting facts: • Found in the fatty parts of food • Removed with the fat when low-fat products are made • Many low-fat foods are supplemented with these vitamins to make up for this • E.g. milk is vitamin A and D enriched

  11. The Vitamins • For each vitamin we will consider: • Functions • Dietary needs and food sources • Deficiency • Toxicity

  12. Thiamin History Functions: • Needed for energy metabolism • E.g. -- required for conversion of pyruvate to acetyl CoA • Needed for nerve and muscle function

  13. Thiamin Recommended Intake • 1.1-1.2 mg/day Food Sources • Found in small amounts in many foods • Easily destroyed by heat (cooking) • Lost in cooking water • Good sources include • Pork products, soy, legumes, vegetables, whole grains, watermelon….(pg 327)

  14. Thiamin Deficiency • Prolonged deficiency leads to beriberi • Results in damage to nervous system and muscles (to include the heart)

  15. Thiamin Deficiency • Symptoms Beriberi: • Dry form- muscle wasting, poor coordination Muscle weakness • Legs heavy, hard to walk, calf pain • Apathy, confusion, memory loss • Anorexia and weight loss • Wet form has additional symptoms of: • edema, irregular heart beat, enlarged heart

  16. In alcoholics thiamin deficiency results in Wernicke-Korsakoff syndrome. • Symtpoms • Mental confusion • Staggering • Rapid eye movements or paralysis of the eye muscles

  17. Thiamin Deficiency • Populations at risk: • Alcoholics • See in alcoholics who obtain the majority of their calories from alcohol • Alcohol inhibits thiamin absorption and hastens its excretion • Cultures that eat primarily refined grains (and little else) • Thiamin deficient moms  infant deaths

  18. The City of New York • DEPARTMENT OF HEALTH AND MENTAL HYGIENE • Michael R. Bloomberg Thomas R. Frieden, m.d., m.p.h. • Mayor Commissioner • _______________________________________________________________ • nyc.gov/health • 2003 Health Alert # 39: • A cluster of infantile thiamine (vitamin B1) deficiency (beri-beri) has been reported in Israel among infants fed a vitamin B1-deficient kosher soy-based formula distributed by Remedia. It is possible that this product may be imported into New York City and there may be children in the Orthodox Jewish community who have consumed it. • The New York City Department of Health and Mental Hygiene (NYCDOHMH) asks that providers report immediately any suspect case of thiamine deficiency among infants who have been fed this product to: • The New York City Poison Control Center at: • 1-212-764-7667 (212-POISONS) or 1-800-222-1222. • Please distribute to Pediatric staff in the Departments of Cardiology, Critical Care, Emergency Medicine, Family Medicine, General Pediatrics, Outpatient Pediatrics, Neonatology, Neurology, and Infectious Disease

  19. Thiamin • Toxicity • None known • Excess thiamin is excreted and not stored

  20. Riboflavin Functions: • Needed for the metabolism of carbohydrates, fats, and proteins • Places a role in Kreb’s cycle • Part of FAD

  21. Riboflavin Recommended Intake: • 1.1 – 1.3 mg/day Food Sources: • Destroyed by ultraviolet light (sun light) • Good sources include: • Milk and milk products • Liver • Whole grain breads and cereals, oatmeal • Clams and squid! • Mushrooms (page 329)

  22. Riboflavin Deficiency Symptoms • Eyes are inflamed and sensitive to light • Cheliosis (cracks at the corners of the mouth) • Sore throat • Inflammation of the tongue and mouth – painful • Inflamed skin, with lesions covered with greasy scales • Anemia

  23. Riboflavin Populations at Risk for Deficiency • alcoholics • any one with a marginal diet • Poor, elderly, eating disorders, drug addicts… Toxicity • None reported • Excess excreted

  24. Niacin Functions • Plays an essential role in energy metabolism • Part of NAD • Needed by every cell of the body

  25. Niacin Recommended Intake: • 14 – 16 mg/day of niacin or of NE • NE = Niacin Equivalents • Niacin can be made from the essential amino acid tryptophan • It takes 60 mg of tryptophan to make 1 mg of niacin • Therefore, 1 NE is 60 mg of tryptophan

  26. Niacin Food Sources: • Sources of complete protein • Dairy, meats, poultry, fish,… • Peanut butter • Tomato paste • Mushrooms • (page 332)

  27. Niacin Deficiency Niacin deficiency disease is called pellagra Symptoms, 4 D’s: • Dermatitis with sun exposure (pg 330) • Diarrhea, vomiting • Dementia • Death Other symptoms: • Inflamed, swollen, red, smooth tongue • Loss of appetite

  28. Niacin • Pellegra - Other interesting information • Originally believed to be caused by infection • Common up to early 1900’s in US and Europe • Many in mental hospitals in south had niacin deficiency, not mental illness • Incidence declined in US after WW II when mandatory enrichment of grains began • Still common in Africa and Asia • Poor bioavailability form corn unless it’s soaked in lime juice

  29. Niacin Toxicity • Tolerable Upper Intake Level (UL) = 35 mg/day • High doses of niacin are commonly used to treat high cholesterol • 1500 -3000 mg/day recommended for treating high cholesterol

  30. Niacin Toxicity Symptoms • Niacin flush • Excessive sweating • Tingling • GI distress • Frequent need to urinate • May mask prostrate cancer symptoms in men • Blurred vision, headaches • Liver damage

  31. Folic Acid = Folate Functions: • Needed for DNA synthesis • Need to make all new cells • E.g. Need to make new RBC • Reduces incidence of neural tube defects • Defects occur in first weeks of pregnancy

  32. Folate • Plays a role in protein synthesis • Breaks down the amino acid homocysteine • High levels of homocysteine increases risk of blood clot formation • May reduce risk some cancers • Pancreatic cancer in men who smoke • Breast cancer in women who drink

  33. Folate • Absorption and Activation • Folate in foods must be acted upon by an intestinal enzyme for it to be absorbed and transported to cells • Folate in cells needs to be activated by vitamin B12 • Process also activates the B12

  34. Folate • Recommended intake: • 400 micrograms/day

  35. Folate • Factors impacting needs • Pregnancy -600 mcg/day • Aspirin, antacids, smoking, oral contraceptives reduce absorption • Some cancer drugs reduce absorption • GI tract damage reduces absorption • Occurs with alcoholism, anorexia • Poor absorption, leads to even more damage to GI tract

  36. Folate • Food Sources • Cooking destroys up to 50% of folate • Oxygen destroys folate • Good sources include: • Green leafy vegetables • Legumes • Fortified cereals and Seeds • Liver • Orange juice (ok, but not great source) pg 341

  37. Folate Folate Deficiency • Impairs cell division and protein synthesis • Symptoms: • Megaloblastic anemia • Fewer red blood cells (RBC) made • RBC larger than normal • RBC do not carry oxygen as well

  38. Folate Deficiency • Confusion, irritability, weakness, fatigue • Related to the anemia • GI tract deterioration • Elevated homocysteine levels • Smooth red tongue • Increased risk neural tube defects

  39. Folate • Toxicity • No known symptoms • May mask a vitamin B12 deficiency • B12 deficiency is VERY serious

  40. Vitamin B12 • Dorothy Crowfoot Hodgkin • Awarded the Nobel prize in chemistry for deducing the structure of vitamin B12 • Took her eight years • Headline in the London paper announcing this read “Nobel Prize for British Wife”

  41. Vitamin B12 Functions: • Needed to activate folate • Therefore, needed for DNA and new cell (RBC) synthesis • Helps maintain myelin sheath around nerve cells

  42. Vitamin B12 Recommended intake: • 2.4 microgams per day Food Sources*: • ONLY found naturally in animal products • Meat, poultry, fish, eggs, dairy, liver…. • Fortified grains *Easily destroyed by microwave cooking

  43. Vitamin B12 Deficiency: • Pernicious anemia (VERY SERIOUS) • Megaloblastic anemia • Nerve damage  creeping paralysis • Smooth sore tongue • Fatigue

  44. Vitamin B12 • Pernicious anemia frequently goes undiagnosed • Pernicious anemia can be masked by high intakes of folate

  45. Vitamin B12 • Gastric by-pass patients and vegans are at elevated risk • Takes several years to develop • Toxicity: • None reported

  46. B6 Functions: • Need for protein and fatty acid metabolism • Need for amino acid metabolism • E.g. For converting tryptophan to other niacin • need to make serotonin form tryptophan • Helps make RBC • Other functions under study

  47. B6 Recommended Intake: • 1.3 mg/day • UL: 100 mg/day Food sources: destroyed by heat • Meat, fish, poultry • Legumes • Seeds and nuts • Liver • Non-citrus fruits

  48. B6 Deficiency: (rare) • Anemia  Weakness and fatigue • Depression, confusion • Abnormal brain waves, convulsions • Greasy dermatitis

  49. B6 Increased risk of deficiency: • Alcoholics • Alcohol contributes to increased B6 breakdown and excretion • Oral contraceptives may increase risk of B6 deficiency Drug INH inactivates B6 INH used to treat tuberculosis

  50. B6 Toxicity: Serious • Stored in muscle cells, toxicity seen with supplements • Symptoms: • Irreversible nerve damage  numbness in hands and feet  Difficult to walk • Convulsions • Insomnia, restlessness

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