http://articles.mercola.com/sites/articles/archive/2005/10/04/test-your-knowledge-of-vitamin-d.aspxThis comes from the Vitamin D Council , a non-profit trying to end the epidemic of vitamin D deficiency. Vitamin D is the most common nutritional deficiency in the United States , and most physicians are clueless about its importance. If you can answerenCommunityServer 2008.5 SP1 (Build: 31106.3070)