Calcium is an essential mineral needed every day for proper nutrition. About 99% of the body's calcium can be found in the bones and teeth. This mineral provides the building blocks that help keep bones and teeth strong and healthy. In addition, calcium helps to support the health of other systems in the body, including the musculoskeletal and nervous systems. Adequate calcium as part of a healthful diet, along with physical activity, may reduce the risk of osteoporosis in later life.