Calcium, we've been taught since grammar school, builds strong bones and teeth. In fact, 99% of the body's supply of calcium goes into the formation and maintenance of bones and teeth. Maintenance is the key word here for calcium is constantly being shuttled from bones to meet other bodily needs (the transmission of nerve impulses, for example, the clotting of blood, the regulation of heart muscle rhythm and the absorption of vitamin B12). Then, if there's an excess, it's redeposited.