Calcium is required by the body to develop and maintain healthy bones, muscles, nervous system, and heart. Calcium carbonate is a common supplement people take when they are not receiving enough calcium in their daily diet. One caplet has approximately the amount of calcium as found in half a litre of milk. 200iu of Vitamin D is included to help in the absorption of calcium. 99% of the calcium in the body is in our bones to become brittle and weak. For our bodies, there is a lifelong, daily nutritional need for calcium.