- Nutrition

Vitamins ABC News -

Vitamins are substances that play an essential part in animal metabolic processes, but which the animals cannot synthesize, chemicals other than proteins, carbohydrates, fats and mineral salts that are essential constituents of the food of animals.

In their absence organisms can develop certain deficiency diseases or other abnormal conditions. Small amounts of vitamins are essential for the regulation of all bodily processes. With the exception of vitamin D, the human body cannot make its own vitamins, and some cannot be stored. Vitamins must therefore be obtained from a food on a daily basis.

The important Vitamins - A, B-complex, C, D, E, and K.

A - is required for healthy skin and mucus membranes, and for night vision. Its absence from the diet leads to a loss in weight and failure of growth in young animals, to the eye diseases; xerophthalmia, and night blindness, and to a general susceptibility to infections. It is thought to help prevent the development of cancer. Vitamin A is structurally related to carotene (the orange stuff in carrots). Carotene is converted into vitamin A in the liver, two molecules of vitamin A are formed from one molecule of beta carotene, hence good sources of carotene, such as green vegetables are good potential sources of vitamin A. Vitamin A is manufactured for sale by extraction from fish-liver oil and by synthesis from beta-ionone.

B1- (Thiamine) releases energy from carbohydrate, alcohol and fat. It is an anti-neuritic factor, the absence of which from the diet of animal leads to the disease beriberi, and to polyneuritis, the most fundamental symptoms of which are general nervous atrophy. Thiamine is a coenzyme which is concerned in a number of important metabolic process.

B2- (Riboflavin) is found to releases energy from protein, fat and carbohydrate. Riboflavin is the part of the original vitamin B2 complex which stimulates growth of rats. It is the precursor of flavoproteins, flavin-adenine dinucleotide and flavin mononucleotide. Good sources of Vitamin B2 are in liver, milk and white of egg, though it occurs widely in nature.

B3- (nicotinic acid or niacin, or 3-pyridine carboxylic) is involved in the oxidative release of energy from food, protects the skin and helps improve circulation. Nicotinic acid is an essential component of mammalian diet. It is the pellagra-preventing factor of vitamin B. The amide, nicotinamide is incorporated into NADH.

This image shows the Vitamin B3, or Niacin in its Coenzyme form, which is called NADH. NADH is the molecule shown as a space-filled model in the center of the image. NADH is shown as part of the Enzyme, Alcohol Dehydrogenase (ADH). Only a part of the ADH protein can be seen here.

The small purple molecule shown underneath NADH is Ethanol, the substrate for this enzyme. The substrate is being held in the active site of ADH, very close to the Co-Enzyme. Together, ADH and Niacin remove a Hydrogen from the alcohol (hence the dehydrogenase part of the name for ADH) as a first step in its detoxification.

B5- (Pantothenic Acid) is an oil which is required by higher animals and some microorganisms. This is considered a member of the Vitamin B group and is present in many natural products and is a constituent of coenzyme A Coenzyme A is involved in many acyl group transfer reaction pathways in the body. Importantly it is involved in the formation of fatty acids, polyketides and the synthesis of terpeniods and steroids. Structurally coenzyme A is composed of adenosine-3',5'-diphosphate and pantetheine phosphate. Pantetheine itself is made from pantothenic and mercaptoethylamine.

B6 - (Pyridoxine) is essential for protein metabolism, and for the formation of hemoglobin - the pigment in the blood that carries oxygen round the body. Its absence from diet is also associated with anemia.

B12 - (cobalamin)- helps protect nerves and is involved in the formation of red blood cells in the bone marrow. Vitamin B12 is also concerned in the biosynthesis of methyl groups of choline and methionine. A deficiency is often due to failure to absorb B12 from the stomach and can be alleviated by giving mg doses with extracts of hog's stomach which contains the intrinsic anti-pernicious anaemia factor (a mucoprotein) which promotes absorption. Vitamin B12 is produced by the growth of certain microorganisms living in your colon and also occurs in the liver.

Bc - (Folic acid or vitamin Bc) is involved in the formation of new cells and therefore essential for the normal growth and development of the fetus. Folic acid and its derivatives are widespread in nature. It is a specific growth factor for certain microorganisms, but in animals the intestinal bacteria provide small quantities needed for growth. The coenzyme forms are actually the reduced products of folic acid. The main function of 5,6,7,8-tetrahydrofolate (THFA) is as a carrier of a C1 (methanoate) unit in the biosynthesis of purines, serines and glycine.

Good sources of Vitamin Bc are most green leaves which are especially rich in the vitamin. Folate or Folic Acid have recently been found to prevent cetain birth defects in humans.

C - (or Ascorbic acid) Nitamin C can be prepared by synthesis from glucose, or extracted from plant sources such as rose hips, black currants or citrus fruits. It is easily oxidized in air. It is essential for the formation of collagen and intercellular material, bone and teeth and for the healing of wounds. It helps maintain elasticity of the skin, aids the absorption of iron and improves resistance to infection. It is used in the treatment of scurvy. May prevent the occurrence and development of cancer. Man is one of the few mammals unable to manufacture ascorbic acid in his liver.

D - is needed for the absorption of calcium and the regulation of calcium levels in the blood. Both vitamins, which have almost identical actions, are used for the prevention and cure of infantile rickets The absence of vitamin D in the food can lead to the development of rickets unless you are exposed to sunlight or u.v. irradiation.; is essential for the normal development of teeth, and is used for treating osteomalacia and dental caries. Vitamin D is necessary for the absorption of Ca and P from the gut. Sunlight activates the metabolism of vitamin D in the body. Good sources of vitamin D are butter, margarine, cheese cream, yogurt, milk

E - Vitamin E is essential for fertility and reproduction. Deficiency in rats leads to loss of fertility. The vitamin is supposed to work as an antioxidant that protects the cells from attack by reactive form of oxygen and free radicals. It is also involved in red blood cell formation. The structure is that of the tocopherols. These are methylated derivatives of tocol. They are widely distributed in vegetable lipids and in the body fat of animals, though animals cannot synthesize them. The E vitamins can protect unsaturated lipids against oxidation.

Four forms of vitamin E are found naturally: alpha - tocopherol, C29H50 O2 is 5,7,8,-trimethyltocol - strongest vitamin E activity. beta - tocopherol C28H48 O2 is 5,8,-trimethyltocol gamma - tocopherol C28H48 O2 is 7,8,-trimethyltocol delta - tocopherol C27H46 O2 is 8,-trimethyltocol.

Good sources of Vitamin E are vegetable oils, nuts and nut oils, seeds, egg yolk, margarine, Parmesan, Cheddar, chickpeas, soya beans, wheat germ, oatmeal, avocados, olives, carrots, parsnips, red peppers, green leafy vegetables.

K - Vitamin K is needed for effective blood clotting. A deficiency is rare because bacteria within the body synthesize vitamin K for you. The absence of Vitamin K is characterized by hemorrhages due to a failure of the blood to clot properly. Vitamin K is associated in some way with prothrombin, which is necessary for clotting. Vitamin K1 can be found naturally in alfalfa oil.

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