The human body needs calcium more than any other mineral. A man weighing 70 kg. contains one kg. of calcium. About 99 per cent of the quantity in the body is used for building strong bones and teeth and the remaining one per cent is used by the blood, muscles and nerves.

Calcium performs many important functions. Without this mineral , the contractions of the heart would be faulty, the muscles would not contract properly to make the limbs move and blood would not clot. Calcium stimulates enzymes in digestion and coordinates the functions of all other minerals in the body.

Calcium is found in milk and milk products, whole wheat, leafy vegetables such as lettuce, spinach, and cabbage , carrots, watercress, oranges, lemons, almonds, figs and walnuts. A daily intake of about 0.4 to 0.6 grams of calcium is considered desirable for an adult. The requirement is larger for growing children and pregnant and lactating women. Deficiency may cause porous and fragile bones, tooth decay, heart palpitations, muscle cramps, insomnia and irritability.

A large increase in the dietary supply of calcium is needed in tetany and when the bones are decalcified due to poor calcium absorption, as in rickets, oesteomalacia and the malabsorption syndrome. Liberal quantity of calcium is also necessary when excessive calcium has been lost from the body as in hyperparathyroidism or chronic renal disease.