The role of Vitamin D in helping to maintain bone density and strength is clear. It is required for the process of moving calcium through the intestinal wall into the bloodstream.
Even though the human body can manufacture Vitamin D under ideal circumstances, there is strong evidence that much of the American population suffers from a deficiency of the nutrient.
This means that supplementation may be important. Two forms of Vitamin D are commonly found in supplements; D-3 (cholecalciferol) and D-2 (ergocalciferol). Vitamin D-3 is more bioactive.
