Vitamin is a chemical compound that the human body needs in small amounts. Vitamins make up one of the major groups of nutrients (food substances necessary for growth and health). Vitamins regulate chemical reactions by which the body converts food into energy and living tissues. There are 13 vitamins. Five of them are produced in the body itself. These vitamins are biotin, niacin, pantothenic acid, vitamin D, and vitamin K. Biotin, pantothenic acid, and vitamin K, which are made by bacteria in the human intestine, are usually produced in sufficient quantities to meet the body's needs. In addition, sunlight on the skin can produce an adequate amount of vitamin D. But the other nine vitamins must be supplied in a person's daily diet.
Showing posts with label V. Show all posts
Showing posts with label V. Show all posts
Thursday, August 26, 2010
Kinds of vitamins
The 13 vitamins are vitamins A; B complex, which is actually a group of 8 vitamins; and C, D, E, and K. Scientists divide vitamins into two general groups, fat-soluble vitamins and water-soluble vitamins. The fat-soluble vitamins--vitamins A, D, E, and K--dissolve in fats. The water-soluble vitamins--the B-complex vitamins and vitamin C--dissolve in water.
Vitamin A
Vitamin A, also known as retinol, occurs naturally only in animals. Eggs, liver, and milk provide much vitamin A. Some plants contain substances called carotenes, or provitamins A, which the body converts into vitamin A. These plants include cantaloupes, carrots, sweet potatoes, dark green leafy vegetables, and deep yellow vegetables.
Vitamin A is essential for the development of babies before birth and the growth of children. It is especially needed for the growth of bones and teeth. Vitamin A keeps the skin healthy and helps produce mucous secretions that build resistance to infection. People who do not get enough vitamin A may develop xerophthalmia, in which the surface of the eye becomes dry and likely to develop infection. Vitamin A also forms part of the two pigments that help the eyes to function normally in light that varies in intensity. Night blindness is an early symptom of a deficiency of vitamin A.
Vitamin A is essential for the development of babies before birth and the growth of children. It is especially needed for the growth of bones and teeth. Vitamin A keeps the skin healthy and helps produce mucous secretions that build resistance to infection. People who do not get enough vitamin A may develop xerophthalmia, in which the surface of the eye becomes dry and likely to develop infection. Vitamin A also forms part of the two pigments that help the eyes to function normally in light that varies in intensity. Night blindness is an early symptom of a deficiency of vitamin A.
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