Known as the "sunshine vitamin" and believed to be important only for bone health, vitamin D is now seen as having a critical function in maintaining the immune system throughout life. 

The RDA for vitamin D is still listed as 200 IU per day. In the last few years, however this vitamin has racked up an impressive list of potential benefits including its role in the support of bone health as well as protection against some of our most debilitating disease processes. 

As a result of these investigations, it is now estimated that up to 85% of the population may be deficient in this important vitamin.