Define Calcium - The Macronutrient?
Calcium is an important mineral found mainly in bone and teeth. It is widely distributed in food substances such as milk, cheese, egg yolk, beans, lentils, nuts, figs, cabbage etc. The total calcium in the body is 25-35 mols (100-170g). About 99% of it is found in bones. It exists as carbonate or phosphate of calcium. About 0.5% is in soft tissues and 0.1% in ECF. The normal levels of plasma calcium are 9-1 1 mg/dl. The calcium in the plasma is of three types:
a) Ionized calcium
b) Protein bound calcium
c) Complexed calcium
About 40% of total calcium is in ionized form. Albumin is the major protein with which calcium is bound. All the three forms of calcium in plasma remain in equilibrium with each other.