Calcium is a nutrient needed by all living organisms, including humans. It is the most abundant mineral in the body and is important for bone health. Humans need calcium to build and maintain strong bones, and 99% of the body’s reliable source of calcium is found in bones and teeth. It is also necessary to maintain healthy communication between the brain and other parts of the body. It plays a role in muscle movement and cardiovascular function. Calcium is found naturally in many foods and food manufacturers add it to some products. There are also nutritional supplements available for purchase. In addition to calcium, people also need vitamin D, as this vitamin helps the body absorb calcium. Vitamin D comes from fish oil, fortified dairy products and exposure to sunlight.