Key Points: Calcium is essential for strong bones and teeth — and also supports muscles, nerves, and heart health. You can get calcium from foods like dairy, leafy greens, fortified drinks, tofu, and canned fish with bones. Your body absorbs calcium best in smaller doses (500 milligrams [mg] or less) and when taken with food. Calcium supplements may help some people but can have risks — talk to your doctor before starting one.