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Wednesday, November 21, 2012
Vitamins and Minerals
Vitamins and minerals are substances required in small amounts, that essential for the normal, healthy functioning of the body normal growth and development, energy productions, body maintenance, and general well being and vitality.
Vitamins are a diverse group of organic substances that cannot be manufactured by the body – except for the vitamin D (which is produced in the skin when it is exposed to sunlight) and niacin (made in the body from the amino acid tryptophan) – and must, therefore, be obtained from food. Absence of one or more vitamins from the diet will, in time, lead to well defined deficiency diseases such as scurvy, beriberi or ostemalacia. The 13 major vitamins, each of which is found in many different foods, are divided into two groups. Fat soluble vitamins- A,D,E, and K – are found in fat or oil containing foods, and are stored in the liver, so that daily intake of these vitamins is not really essential. In fact, excessive consumption of fat soluble vitamins, usually by taking too many vitamins tablets, can be harmful. Deficiency of fat soluble vitamins is usually caused by disorders that stop the intestine absorbing fat efficiently. Water soluble vitamins- the B complex vitamins and vitamin C are not stored in the body (apart from vitamin B 12). To avoid deficiency, therefore, food containing water soluble vitamins should be eaten each day to keep supplies “topped up”. Because water soluble vitamins are destroyed by prolonged cooking, processing and storage, fresh or lightly cooked foods make the best sources.
Minerals are simple chemical elements that cannot be made by the body but must be present in the diet o maintain good health. There are 20 minerals known to be essential in small amounts, in addition to carbon, oxygen, hydrogen and nitrogen, which are needed in large amounts to construct the body’s framework. Some, including calcium phosphorous, potassium, sulfur, sodium magnesium and chlorine and some traces of minerals such as iron cobalt copper zinc molybdenum iodine and selenium are also important for mammals.