Calcium is a chemical element which is essential for living organisms, including humans. Calcium's chemical symbol is Ca. It is found in many foods. We need to consume a certain amount of calcium to build and maintain strong bones and healthy communication between the brain and various parts of the body.The National Health Service (NHS) 1, UK, says there is more calcium in the human body than any other mineral.itamin D helps our bodies absorb and retain calcium in the bones. According to the NIH (National Institutes of Health) 3, approximately 43% of all American adults take dietary supplements - 70% of adult females do. Users increase their calcium daily intake by about an average of 300 mg per day through supplements.