VITAMINS

• Vitamin A (Retinol) - Vitamin A is found in food from animal sources and it is also produced synthetically. Vitamin A is important for the eyes and skin, and for normal growth. Its function is to maintain mucous membranes and for visual acuity in dim light , growth and bone development. Bile is necessary for absoprtion. Do not take more vitamin A than is prescribed for you or than is recommended on the package. Too much vitamin A can be dangerous. Large amounts are toxic.
• Vitamin B1 (thiamin) - It involves in carbohydrate metabolism. sometimes called aneurin, is a water-soluble vitamin of the B complex (vitamin B1), whose phosphate derivatives are involved in many cellular processes. Thiamine is found in a wide variety of foods at low concentrations. Yeast and pork are the most highly concentrated sources of thiamine. Thiamine is mainly the transport form of the vitamin, while the active forms are phosphorylated thiamine derivatives.
• Vitamin B2 ( riboflavin) -  is manufactured in the body by the intestinal flora and is easily absorbed, although very small quantities are stored, so there is a constant need for this vitamin. It is required by the body to use oxygen and the metabolism of amino acids, fatty acids, and carbohydrates.
• Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine) - Coenxyme for transamination, trnassulfuration and decarboxylation. It converts glycogen to glucose. It is required for the synthesis of the neurotransmitters serotonin and norepinephrine and for myelin formation. Major sources of vitamin B6 include: cereal grains, legumes, vegetables (carrots, spinach, peas), potatoes, milk, cheese, eggs, fish, liver, meat, and flour. 
• Vitamin B12 (hydroxycobalamin) - Vitamin B12 is an essential water-soluble vitamin that is commonly found in a variety of foods such as fish, shellfish, meat, and dairy products. Vitamin B12 is frequently used in combination with other B vitamins in a vitamin B complex formulation. It helps maintain healthy nerve cells and red blood cells and is also needed to make DNA, the genetic material in all cells. Intrinsic factor is necessary for absorption. The human body stores several years' worth of vitamin B12, so nutritional deficiency of this vitamin is extremely rare.
• Vitamin C (ascorbic acid) - It is most easily destroyed vitamin. Vitamin C is a water-soluble vitamin that has a number of biological functions. Acting as an antioxidant, one of vitamin C’s important functions is to protect LDL cholesterol from oxidative damage. (Only when LDL is damaged does cholesterol appear to lead to heart disease, and vitamin C may be one of the most important antioxidant protectors of LDL.). Vitamin C may also protect against heart disease by reducing the stiffness of arteries and the tendency of platelets to clump together. It synthesis collagen, helps in formation of intercellular cement and facilitation of iron absorption.
• Vitamin D (cholecalciferol) - is a group of fat-soluble prohormones, the two major forms of which are vitamin D2 (or ergocalciferol) and vitamin D3 (or cholecalciferol). Vitamin D obtained from sun exposure, food, and supplements, is biologically inert and must undergo two hydroxylation reactions to be activated in the body through ultraviolet light. It increases absorpption of calcium and phosphorus and helps in bone mineralization. Vitamin D plays a number of other roles in human health including inhibition of calcitonin release from the thyroid gland. Calcitonin acts directly on osteoclasts, resulting in inhibition of bone resorption and cartilage degradation. Vitamin D can also inhibit parathyroid hormone secretion from the parathyroid gland, modulate neuromuscular and immune function and reduce inflammation.
• Vitamin E (tocopherol) - Vitamin E is found in foods such as vegetable oils and shortening, meat, eggs, milk, and leafy vegetables. Vitamin E is important for many processes in the body. It reduces oxidation of vitamin A, phospholipids and polysaturated fatty acids. Vitamin E is found naturally in some foods, added to others, and available as a dietary supplement. Vitamin E is the collective name for a group of fat-soluble compounds with distinctive antioxidant activities. Antioxidants protect cells from the damaging effects of free radicals, which are molecules that contain an unshared electron. Free radicals damage cells and might contribute to the development of cardiovascular disease and cancer.
• Vitamin K (phylloquinone) - a group of lipophilic, hydrophobic vitamins that are needed for the posttranslational modification of certain proteins, mostly required for blood coagulation. It is normally produced by bacteria in the large intestine, with the help of normal flora, and bile necessary for absorption. Vitamin K deficiency exists when chronic failure to eat sufficient amounts of vitamin K results in a tendency for spontaneous bleeding or in prolonged and excessive bleeding with trauma or injury.
• Folacin (B9 or folic acid) - Ascorbic acid is necessary for utilization. Folic acid is a water-soluable vitamin belonging to the B-complex group of vitamins. These vitamins help the body break down complex carbohydrates into simple sugars to be used for energy. Folate is necessary for the production and maintenance of new cells. It is especially important during periods of rapid cell division and growth such as infancy and pregnancy. Folate is needed to synthesize nucleic acids (most notably thymine, but also purine bases).
• Niacin (B3 or nicotinnamide or nicotinic acid) - amino acid trytophaan is a precursor. It is a watre-soluble vitamin that derivative of pyridine, with a carboxyl group (COOH) at the 3-position. Niacin is used to treat and prevent a lack of natural niacin in the body, and to lower cholesterol and triglycerides in the blood. It is also used to lower the risk of heart attack in people with high cholesterol who have already had a heart attack.