NATURES AID CHEWABLE Calcium is needed for the maintenance of normal bones and normal teeth. Calcium contributes to normal muscle function, blood clotting, energy-yielding metabolism, normal neurotransmission and normal function of digestive enzymes. Calcium has a role in the process of cell division and specialisation. Vitamin D contributes to normal absorption/utilisation of calcium and phosphorus, and to normal blood calcium levels. Calcium and vitamin D help to reduce the loss of bone mineral in post-menopausal women. Low bone mineral density is a risk factor for osteoporotic bone fractures.