Classification of Vitamins - The Low Down
A person requires only about 350g or 12 oz of vitamins from about 2000lb of food consumed annually. Vitamins, often considered accessory nutrients do not supply energy, are not basic building units for other compounds, and do not contribute substantially to the body's mass. Nevertheless, a prolounged inadequate intake of a particular vitamin can trigger symptoms of vitamin deficiency and lead to severe medical complications. A good example would be symptoms of thamin deficiency which can occure after only 2 weeks on a thamin free diet, and symptoms of vitamin C deficiency appear after 3 or 4 weeks. As the other extreme, consuming some fat soluable vitamins in excess can produce a toaxis overdose manifested by hair loss, irregularities in bone formatio, fetal malformation, hemmorrhage, bone fractures, abnormal live function, and ultimately death.
Thirteen differen vitamins have been isolated, analyzed, classified, and synthesized, and have RDA established levels. Vitamins are classified as either fat soluble. Vitamins A, D, E, and K, or are water soluable; vitamin C and B complex vitamins: vitamin B6 (pryidoxine), vitamin B1 (thiamin), Bitamin B2 (riboflavin), niacin (nicotinic acid), pantothenic acid, biotin, folic acid, and vitamin B12 (cobalamin).
Fat soluble vitamins dissolve and store in the body's fatty tissue and do not require daily intake. in fact symptoms of a fat soluable vitamin insufficiency may not apperar for years. Dietry lipids provide the source of fat soluble vitamins. the Liver stores vitamins A, D, and K whereas vitamin E distributes throughout the body's fatty tissue. PRolonged intake of a fat free diet acceleraets a fat soluble vitamin insufficiency.
Vitamin C (ascorbic acid) and B complex group constitute the nine waer soluable vitamins. They act largly as coenzymes to form an active enzyme that accelerates interconversion of chemical compounds. Coenxymes participate directly in chemical reactions; where the reaction runs its course. Coenzymes remain intact and participate in further reactions. Water soluable vitamins play an essential role as part of coenzymes in the cell's energy generating reactions. Because of their solubility in water, water soluable vitamins disperse in the body fluids without appreciable storage, and the excess voids in the urine. In the diet regulary contains less than 50% of the recommended values for water soluable vitamins, marginal deficiencies may develope within 4 weeks. The B complex vitamin serves as coenzymes in energy yielding reactions during carbohydrates, fat and protein breakdown. They also contribute to hemoglobin synthesis and red blood cell formation. Vitamin C acts as a cofactor in enzymatic reactions and as a scavenger of free radicals in antioxidative processes and contributes to collagen synthesis and maintaining the intracellular matrix of bone and cartilage.
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