Calcium is the most abundant divalent cation of the body, representing about 1.5% to 2 % of total body weight.
Calcium in the body roses from an average of 24 grams at birth to about 1300 grams at maturity.
Over 99% of the total calcium of the body located in the bones, where it accounts for 39% of the total body bone mineral content and in the teeth, mostly as hydroxyapatite.
Physical Function
Structural component of bones and teeth; role in intracellular and hormonal secretion regulation, muscle contraction, blood clotting, and activation of some enzyme systems.
The calcium in bones serves as a reservoir for calcium that is needed throughout the body.
Calcium also is the key factor in normal transmission of nerve impulses. The movement of calcium into nerve cells triggers the release of neurotransmitter at the junction between nerves.
Deficiency symptoms
The symptoms of calcium deficiency includes rickets, osteomalacia, osteoporosis, scurvy, tetany, parathyroid hyperplasia, stunted growth, laryngospasm.
Deficiency of calcium lowers the body resistance and for the children become as easy prey to respiratory and intestinal infections.
Poor calcium intake affects mostly bone and muscle. Rickets occurs in children when the amount of calcium accretion per unit of bone matrix is deficient.
Hypocalcemia may result in tetany, a condition characterized by intermittent muscle contractions that fail to relax, especially in muscles of the arms and legs.
Food sources
Calcium is present in foods and dietary supplements as relatively insoluble salts.
Food sources of calcium include milk, milk products, sardines, clams, oysters, turnip greens, broccoli, legumes and dried fruits.
Majority of dietary calcium in industrialized countries comes from milk products.
When substantial amounts of grains are consumed, for like breads or as maize, these can be important sources, although the calcium in cereals rends to be less bioavailable than that in dairy products.
Mineral of Calcium in Human Body