Calcium: most abundant mineral in the body. Needs vitamin D for good absorption. Necessary for synthesis of B12. Works with phosphorus to build sound teeth and bones, with magnesium for cardiovascular health and skeletal strength. Helps blood clotting, lowers blood pressure, prevents muscle cramping, maintains nervous system health, controls anxiety and depression, and insures high quality rest and sleep. May help prevent colon cancer and osteoporosis. Aluminum-based antacids interfere with calcium absorption. Antibiotics and cortico-steroid drugs increase calcium needs. Calcium citrate has the best record of absorbency. Food sources: green vegetables, milk and dairy products, sea vegetables, tofu, molasses, shellfish.