Direct sunlight promotes Vitamin D.

• Position: Your Life

Vitamin D is manufactured in the skin after direct exposure to UV light--accounting for 90% of the daily recommended intake. Researchers at the University of Michigan Health System, Ann Arbor, are finding this often-ignored, bone-building vitamin can play a significant role in the prevention of heart disease and the function of other critical body systems.

Regular and moderate exposure to sunlight is the best way to help the body manufacture the Vitamin D it needs. Vitamin D deficiency is associated with more than 100,000 additional cases of cancer and 30,000 annual cancer deaths. Moreover, sun exposure in small doses is not linked to melanoma. Rather, intermitent sunburn--particularly among those who are predisposed to it--is believed to be the risk factor.

"I think an overall shift in thought on the Vitamin D system is in order," argues Robert Simpson...