"Emerging research supports the possible role of vitamin D in protecting against cancer, heart disease, fractures and falls, autoimmune diseases, influenza, type 2 diabetes, and depression. Many health care providers have increased their recommendations for vitamin D supplementation to at least 1,000 IU."
http://www.medscape.com/viewarticle/731722?src=mp&spon=17&uac=144206BZ