In 1919, Sir Edward Mellanby discovered vitamin D and the role it plays in the development of the childhood bone disease, rickets. Since then, vitamin D has been recognized for its role in enhancing calcium absorption, thereby promoting good bone health. In fact, vitamin D deficiency can also lead to osteomalacia—weak bones in adults. But, new research is suggesting various other roles for vitamin D as well. Adequate vitamin D levels are thought to reduce risk of breast, colon and prostate cancers and play a preventative role in multiple sclerosis, diabetes and rheumatoid arthritis. Finally, emerging research suggests that vitamin D may be involved in optimal functioning of the immune system, mental activities and in reducing risk of periodontal disease—a chronic inflammatory gum disease that can lead to tooth loss.