Body contains calcium in greater amount than any other element. About 2 percent of the body of an adult is due to calcium, out of which about 99 percent is present in bones and teeth.
Calcium is the most important factor in building skeleton and teeth, and it is all the important during growing years. Normal behavior of heart and nervous system, blood-clotting process, etc., depends on the presence of calcium.
The available information on the retention of calcium by human body has suggested the desirability of a daily intake of about 0.4 to 0.6 gm. Of calcium by an adult. In case of growing children, pregnant and lactating mothers, the requirement increases to 1.0gm per day.
Sources of Calcium
Milk and milk products are the richest sources of calcium. Green leafy vegetables, such as spinach, amaranth and rich in calcium but these are oxalate-rich foods. The oxalate and calcium form insoluble calcium oxelate and thus render the calcium of no avail to the body,as in this form it can not be assimilated.
Phosphorus ranks a second in regard to the total amount of minerals present in the body and constitutes about one-fourth of entire body minerals. About 80 percent of the phosphorus is found in bones combined with calcium and the rest is found in soft tissues and body fluids. Besides this, phosphorus plays an important role in various functions of the body which are:
(a) Formation of teeth and bones
(b) Maintenance of acid-base balance of the blood.
(c) Supply of energy to the muscles for concentration.
(d) In the form of enzymes, they regulate carbohydrate metabolism.
About one gm. or more of phosphorus should be supplied in the diet daily. However, phosphorus deficiency is rarely encountered in Indian diets because the diets consumed are predominantly based on cereals.
Sources of Phosphorus
Phosphorus is found in good amount in the foods which are rich in protein and calcium. Thus milk, cheese, egg yolk, meat, fish are good sources of phosphorus. The higher phosphorus content of the whole-grain products is misleading because of the greater content of phytin phosphorus, which is not readily assimilated and used by the body.
Deficiency of Calcium and Phosphorus
Lower intakes of calcium may result in retarded calcification of bones and teeth. Acute deficiency of calcium is not usually seen unless there is a simultaneous deficiency of vitamin D which leads to stunted growth and rickets as evidenced by bowing of the legs, enlargement of the ankles and wrists, and a hollow chest.
It is general misconception that adults do not suffer from calcium deficiency. Calcium deficiency leads to thin, fragile bones which break easily and heal with difficulty. Osteomalacia and osteoporosis may result from the deficiency of calcium and Vitamin D.