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The Water-Soluble Vitamins

The Water-Soluble Vitamins. B vitamins Vitamin C. B Vitamins. Originally thought to be one vitamin 8 of them Act primarily as coenzymes in metabolic pathways Important for ATP production!!! Important for MANY additional functions. B Vitamins.

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The Water-Soluble Vitamins

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  1. The Water-Soluble Vitamins B vitamins Vitamin C

  2. B Vitamins • Originally thought to be one vitamin • 8 of them • Act primarily as coenzymes in metabolic pathways • Important for ATP production!!! • Important for MANY additional functions.

  3. B Vitamins • Dietary requirement is linked closely to metabolic rate (i.e., production) • Ruminant requirements met by rumen bacterial synthesis • Hindgut bacterial synthesis and absorption is insufficient to meet full requirements for a horse

  4. B Vitamins-Sources • VARIETY of foods! • Plant sources • Found in fibrous portion of plants • Most cereals and grain products are enriched • Animal sources • Liver • Milk • Egg • Beef, pork and chicken

  5. B Vitamin-Deficiency • LOTS of symptoms including fatigue • Specific diseases for each vitamin deficiency (e.g., beriberi, pellagra)

  6. Thiamin (B1) • Present in tissues as thiamin pyrophosphate (TPP) • TPP is an essential coenzyme for oxidative decarboxylation of alpha-keto acids • pyruvate to acetyl CoA • Deficiency • beriberi in humans • polyneuritis in birds • bracken fern poisoning in ruminants and horses • antithiamin activity

  7. Polyneuritis

  8. Riboflavin (B2) • Essential constituent of flavoproteins (e.g., FAD) • Hydrogen carrier in glycolysis, TCA and oxidative phosphorylation • Deficiency • curled toe paralysis in birds

  9. Curled Toe Paralysis

  10. Nicotinamide (niacin) • Amide derivative of nicotinic acid • Can be synthesized from trytophan • Essential constituent of NAD and NADP • Hydrogen carrier catalyzed by dehydrogenase enzymes • ATP synthesis • Deficiency • Pellagra in farm animals and humans • Fiery inflammation of tongue, mouth and upper esophagus

  11. Pyridoxine (B6) • Active form is pyridoxal phosphate • Essential coenzyme for transamination and decarboxylation of amino acids • Deficiency • None in farm animals

  12. Pantothenic acid • Dipeptide derivative of alanine and a butyric acid derivative • Essential constituent of coenzyme A • Acyl transfer • Deficiency • None in farm animals

  13. Folic acid (folacin) • Tetrahydrafolic acid is active functional form • Carrier of one-carbon (e.g., methyl) groups • Deficiency • None in farm animals

  14. Focus on Folate • Important for proper neural development during fetal growth. • Controlled, clinical intervention trial showed decreased risk of spina bifida in women supplemented with folate • “problems” with study • Current recommendation

  15. More on Folate • May also reduce (greatly) risk for heart disease • Dietary Sources • Animal sources • Liver • Crab meat • Plant sources • Spinach • Lentils • Dried beans • Fortified cereal products!

  16. Biotin • Coenzyme involving CO2 transfer • acetyl CoA to malonyl CoA • Propionyl CoA to methylmalonyl CoA • Pyruvate to oxaloacetate • Deficiency • Fatty liver and kidney syndrome, a fatal metabolic disorder in chicks and turkey poults • Raw egg white (avidin) can block absorption

  17. Cyanocobalamin (B12) • Active form is cyanide derivative of cobalamin • Cobalt is an integral component • Coenzyme for numerous reactions • Methylmalonyl CoA to succinyl CoA • DNA synthesis • Transmethylation (methionine synthesis) • Deficiency • Pernicious anemia in humans (lack intrinsic factor) • Wasting disease in ruminants (Co deficiency)

  18. Vitamin C • Discovery • Sailors used to die from disease called “scurvy.” • James Lind conducted first human nutrition intervention trial and found that citrus fruits prevented scurvy. • Why Brits are called “limeys.”

  19. Vitamin C • Ascorbic acid • Antioxidant • Protects cells from free radicals • Protects iron from oxidative damage, thus enhancing iron absorption in the gut • Required for various hydroxylation reactions • proline to hydroxyproline for collagen synthesis Deficiency • Not in farm animals • Scurvy in humans

  20. Vitamin CRoles in the Body • Stress (e.g., infections, smoking) • Mechanism unknown, but vitamin C requirements increase during stress • Common cold? • Disease prevention? • Cancer, heart disease: stay tuned…

  21. Vitamin CDeficiency • Scurvy • Bleeding gums • Small red spots on skin • Rough skin • Wounds fail to heal • Weak bones and teeth • Anemia and infections

  22. What about vitamin supplements? • Remember, most supplements that you can buy aren’t actually vitamins. • Megadosing (> 500% RDA) almost never recommended • No harm in “one-a-day” type • Probably prudent in • Those who do not eat certain types of food • People with generally poor diets • Don’t get lazy BECAUSE you take a supplement.

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