Vitamin D3 is a crucial nutrient for overall health, specifically maintaining strong muscles, bones, teeth and immune system. However, millions of individuals are deficient in this life-sustaining vitamin. In addition to supporting bone health‚ research shows that D3 deficiency is linked to a host of conditions that present serious health risks. Zahler's Vitamin D3 provides all the benefits of vitamin D without the risk of unprotected exposure to UVB rays. More about Vitamin D3: Officially known as cholecalciferol, Vitamin D’s nickname, the “sunshine vitamin,” offers insight into one of the ways humans can get the vitamin. Aside from exposure to sunlight, you can also obtain Vitamin D3 by eating certain foods, such as fish, eggs, and milk fortified with the vitamin. However, many people do not have adequate levels of Vitamin D3 in their systems and therefore require supplementation.