Lack of vitamin D, the sunshine vitamin, may increase the risk of cancer, other disorders

Living in the rainy Pacific Northwest, I've often wondered about getting enough vitamin D, the sunshine vitamin.

People who live in northern climates may be deficient in vitamin D and may be at an increased risk of certain diseases and disorders, recent studies show.

In a Feb. 13, 2008, article, "Does Our Lack of Sun Put Your Health in Danger?" The Seattle Times reports that low levels of vitamin D can:

• Raise your risk of cancer.
• Increase susceptibility to heart attack, diabetes, and other disorders.
• Partially account for higher rates of multiple sclerosis in northern areas.

Because people use sunscreen, a seasonal shortfall of vitamin D has become  a year-round condition for many. A 15-minute exposure to the summer sun to your arms and legs only can generate 5,000 international units of the vitamin. One expert, quoted in The Times article, recommends sensible sun exposure that shields the face and stops far short of sunburn.

Vitamin D, long associated only with its role in bone formation, is actually active throughout the human body, powerfully influencing immune system responses and cell defenses, according to an article in Scientific American, November 2007.

Vitamin D supplements could address the high prevalence of vitamin D deficiency in temperate zones, but how much people should take is still being debated. See page 5 of the Scientific American article for suggestions.

If people take too much vitamin D, it can trigger dangerous calcium deposits in kidneys and blood vessels, according to The Times article. However, it takes a significant amount for this to occur: more than 10,000 IU a day for a year.

How does your city rank in the amount of sunshine it receives?

Here is a listing of the top 101 cities, with a population of 50,000 plus, in the U.S. that have the lowest average amount of sunshine.

My next three posts on The Survive and Thrive Boomer Guide will cover cover warm weather topics:

• Retiring where it's warm in the U.S.
• Retiring where it's warm abroad.
• A great vacation treat in Florida, art in a botanical garden.