Not enough sun?

While too much sun can be bad for us, some sun exposure is necessary. That's because the same ultraviolet rays that damage skin also cause it to produce an important nutritional component, vitamin D. Vitamin D plays a major role in developing and maintaining strong bones. We use it to fortify food, especially milk. This practice reduced rickets from an all-too-common childhood skeletal disease to one that's rare.

Some researchers worry that some women of childbearing age, particularly African-Americans, may be deficient in vitamin D and may be putting their children at risk. That's because darker skin doesn't create vitamin D as efficiently from the sun, and many nonwhite people have more difficulty dealing with lactose in milk.

Meanwhile, other researchers are looking at evidence that vitamin D may play another important role. It may reduce the risk of certain types of cancer. Scientists are working to understand why, according to a recent National Cancer Institute study, the chances of dying from breast, colon, ovarian and prostate cancer were reduced by 10 percent or more for people living in sunnier states.

So while the problems with too much sunlight may be well-known, the role of sunlight and vitamin D may still be a mystery.

Resources

Information about vitamin D from the National Institutes of Health

New York Times article on research into vitamin D and cancer (registration required)

A Science News Online article about a study looking at "an epidemic of Vitamin D deficiency"