"Vitamin D increasingly seems important for preventing and even
treating many types of cancer.

In the last three months alone, four separate studies found it helped
protect against lymphoma and cancers of the prostate, lung and,
ironically, the skin. The strongest evidence is for colon cancer.

Many people aren't getting enough vitamin D. It's hard to do from food
and fortified milk alone, and supplements are problematic.

So the thinking is this: Even if too much sun leads to skin cancer,
which is rarely deadly, too little sun may be worse.

No one is suggesting that people fry on a beach. But many scientists
believe that "safe sun" ? 15 minutes or so a few times a week
without
sunscreen ? is not only possible but helpful to health."

Source: http://news.yahoo.com/s/ap/sunshine___cancer