Calcium is a mineral that is required for strong teeth and bones. It is also beneficial to the health of blood vessels, muscles, and nerves, as well as hormone function. Calcium is a mineral that is necessary for the proper functioning of several systems in the body. You must maintain enough calcium levels in order for your heart, neurological system, and muscles to operate effectively. Calcium citrate is the most common kind of calcium supplement. Calcium citrate is more easily absorbed than calcium carbonate. Calcium citrate does not require stomach acid to be absorbed, making it a better alternative for persons who use heartburn medication or have digestive disorders.