Vitamin D3 (as cholecalciferol) is needed by the body to regulate phosphorus and calcium levels for healthy bones, teeth and heart. It is beneficial for bone density and structure as well as for immune, cardiovascular and cellular function. It plays a role in most organs and systems of the body and affects the chemical messengers of the immune system. The Sky Premium Life D3 is the same as the one produced by the body when our skin is exposed to sunlight. Vitamin D is important for a number of reasons: Contributes to the normal absorption / utilization of calcium and phosphorus. At normal blood calcium levels. In maintaining normal bones. In maintaining normal muscle function. In maintaining normal teeth. In the normal functioning of the immune system. Vitamin D plays a role in the process of cell division. It regulates insulin levels and helps manage diabetes. Supports lung function and cardiovascular health.