Do You Need More Vitamin D?

The primary source of this vitamin comes from exposure to the sun. The body already contains precursors for vitamin D. It is converted to a usable form when ultraviolet B (UVB) rays from the sun hit the skin. About 10 to 20 minutes of exposure to the sun (without sunscreen) a day can generate an adequate amount of usable vitamin D. It's important to put sunscreen on after 20 minutes to prevent burning and protect against skin cancer.