The importance of calcium in the diet lies primarily in its role in building and maintaining strong bones and teeth. Calcium facilitates various bodily functions, including nerve transmission, muscle contraction, and blood clotting. Adequate calcium intake is essential for individuals of all ages, but particularly crucial during childhood and adolescence when bone growth occurs. Additionally, adequate calcium levels may help prevent osteoporosis, a condition characterized by weak and brittle bones, particularly in older adults. Sources include dairy products, leafy greens, and fortified foods.