Calcium is the most abundant mineral in the body. Ninety-nine per cent of calcium is in our bones and teeth, with the remainder in our tissues and blood. Calcium is important in the formation of the skeletal frame, but as we age our ability to make calcium diminishes. In women, it is regulated by oestrogen in bone health, so is adversely affected when the menopause occurs. It is at this time and, during pregnancy for the formation of bones in the foetus, that adequate calcium intake is critical. Calcium is best absorbed in conjunction with vitamins D3 and K2. With the latter, it is also effective in blood-clotting. Apart from dairy, calcium is highest in sardines, salmon and orange juice.