The metallic element present in chalk and other forms of lime. The chief preparations used in medicine are calcium carbonate (chalk), calcium chloride, calcium gluconate, calcium hydroxide (slaked lime), liquor of calcium hydroxide (lime-water), calcium lactate, and calcium phosphate. Calcium gluconate is freely soluble in water and is used in conditions in which calcium should be given by injection.
Calcium is a most important element in diet; the chief sources of it are milk and cheese. Calcium is especially needed by the growing child and the pregnant and nursing mother. The uptake of calcium by the baby is helped by vitamin D (see APPENDIX 5: VITAMINS). A deﬁciency of calcium may cause TETANY, and an excess may result in the development of CALCULI (stones) in the KIDNEYS or gallbladder (see LIVER).
The recommended daily intakes of calcium are: 500 mg for children, 700 mg for adolescents, 500–900 mg for adults and 1,200 mg for pregnant or nursing mothers.