Minerals and their Importance in Nutrition

MAGNESIUM

All human tissues contain small amounts of magnesium. The Adult human body contains about 25 gms. of this mineral. The greater part of this amount is present in bones in combination with phosphate and carbonate. Bone ashes contain less than one per cent magnesium. About one-fifty of the total magnesium in the body is present in the soft tissues, where it is mainly bound to protein. Next to potassium, magnesium is the predominant metallic action in living cells. The bones seem to provide a reserve supply of this mineral in case of shortage elsewhere in the body.

Biochemists call magnesium the " cool, alkaline, refreshing, sleep-promoting mineral". Magnesium helps one keep calm and cool during the sweltering summer months. It aids in keeping nerves relaxed and normally balanced. It is necessary for all muscular activity. This mineral is in activator for most of the enzyme system involving carbohydrate, fat and protein in energy-producing reactions. It is involved in the production of lecithin which prevents building up of cholesterol and consequent arteriosclerosis. Magnesium promotes a healthier cardiovascular system and aids in fighting depression. It helps prevent calcium deposits in kidneys and gallstones and also brings relief from indigestion.

Magnesium is widely distributed in foods. It is a part of the chlorophyll in green vegetables. Other good sources of this mineral are nuts, soyabeans, alfalfa, apples, figs, lemons, peaches, almonds, whole grains, brown rice, sunflower seeds and sesame seeds. The recommended dietary allowances for magnesium are 350 mg. per day for adult man, 300 mg. for women and 450 me. during pregnancy and lactation. Deficiency can lead to kidney damage and kidney stones, muscle cramps, arteriosclerosis, heart attack, epileptic seizures, nervous irritability, marked depression and confusion, impaired protein metabolism and premature wrinkles.

Chronic alcoholics often show a low plasma magnesium concentration and a high urinary output. They may, therefore, require magnesium therapy especially in an acute attack of delirium tremens. Magnesium has also proved useful in bladder and urinary problems and in epileptic seizure. This mineral together with vitamin B6 or pyridoxine has also been found effective in the prevention and treatment of kidney stones. Magnesium can be taken in therapeutic doses up to 700 mg. a day.

SODIUM

Sodium Chloride , the chemical name for common salt, contains 39 per cent of sodium, an element which never occurs in free form in nature. It is found in an associated form with many minerals especially in plentiful amounts with chlorine. The body of a healthy person weighing about 65 kg. contains 256 g. of sodium chloride. Of this the major part, just over half, is in the extra-cellular fluid. About 96 g. is in bone and less than 32 g. in the cells.

Sodium is the most abundant : chemical in the extra-cellular fluid of the body. It acts with other electrolytes, especially potassium, in the intracellular fluid, to regulate the osmotic pressure and maintain a proper water balance within the body. It is a major factor in maintaining acid-base equilibrium, in transmitting nerve impulses, and in relaxing muscles. It is also required for glucose absorption and for the transport of other nutrients across cell membranes. Sodium can help prevent catarrh. It promotes a clear brain, resulting in a better disposition and less mental fatigue. Because of its influence on calcium, sodium can also help dissolve any stones forming within the body. It is also essential for the production of hydrochloric acid in the stomach and plays a part in many other glandular secretions.

There is some natural salt in every food we eat. Vegetable foods rich in sodium are celery, cucumbers, watermelon, lemons, oranges, grapefruit, beet-tops, cabbage, lettuce, corn, lady’s fingers, apple, berries, pears, squash, pumpkin, peaches, lentils, almonds and walnuts. Animal food sources include shell fish, lean beef, kidney, bacon and cheese. The sodium chloride requirements for persons living in the tropics have been estimated at 10 to 15 g. per day for adults who are engaged in light work and 15 to 20 g. for those engaged in hard work. The requirements of children are from five to 10 g. and those for adolescent boys and girls from 10 to 25 g.

Both deficiency and excess of salt may produce adverse effects o the human body. Deficiencies of sodium are, however, rare and may be caused by excessive sweating, prolonged use of diuretics, or chronic diarrhea. Deficiency may lead to nausea, muscular weakness, heat exhaustion, mental apathy and respiratory failure. Over-supply of sodium is a more common problem because of overuse of dietary sodium chloride or common salt. Too much sodium may lead to water retention, high blood pressure, stomach ulcers, stomach cancer, hardening of arteries and heart disease.

In case of mild deficiency of sodium chloride, taking a teaspoon of common salt in one half litre of water or any fruit juice quickly restores the health. In severe conditions, however, administration of sodium chloride in the form of normal saline by intravenous drip may be restored to. The adverse effects of excessive use of sodium chloride can be rectified by avoiding the use of common salt.