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May/June 2009 Alternative Health
Get a Little Sunny D this Summer

by David Stauth

As summer approaches and pale Pacific Northwesterners get ready to slather on the sunscreen, a note of caution is in order - a little sunshine is good for you.

Studies increasingly are suggesting the value of vitamin D - often known as the sunshine vitamin, because that's one way you can obtain it - in everything from bone metabolism to maintaining muscle strength, immune function, reducing hypertension and possibly even playing a role in prevention of cancer and autoimmune disease.

Summer is when most people finally get enough vitamin D from sun exposure, and this time in the sun also helps build stores in fat for use during the dark days of winter. But research has suggested that as many as a billion people around the world may now be vitamin D deficient, posing possibly serious health threats.

"The old theory was that if you had enough vitamin D to prevent rickets and osteomalacia, two skeletal disorders, you were okay," says Victoria Drake, a research associate in the Linus Pauling Institute at Oregon State University, and manager of its Micronutrient Information Center. "But new research is now raising awareness about the possible relationships between vitamin D and cancer, particularly colorectal, breast, ovarian and prostate cancers. There are also potential links to cardiovascular disease, and autoimmune diseases such as multiple sclerosis and rheumatoid arthritis."

Experts still argue about how much vitamin D is enough, and some feel that the optimal amount is several times higher than the adequate intake level set by the Food and Nutrition Board of the Institute of Medicine, which is 200 international units (IU) per day for adults ages 19 to 50.

What's clear, however, is that many Americans are not getting even those minimal amounts, especially those with dark skin colors - one study reported that 42 percent of African American women were vitamin D deficient.

As a result, Drake says, many doctors are increasingly starting to test their patients for deficiency of this vitamin, especially in the temperate zones above 40 degrees latitude - a line running roughly from Philadelphia to Denver and through Northern California. Residents of the Pacific Northwest, with its northern latitudes and eternally cloudy winters, are especially vulnerable. Inexpensive supplements are frequently prescribed.

"My own doctor said that he frequently tests for vitamin D status, and that vitamin D deficiency is prevalent in his patient population," Drake says. "Experts are now talking about a phenomenon they call 'vitamin D winter.'"

One recent study referred to vitamin D deficiency as "a major unrecognized epidemic in the older adult population" and recommended routine blood testing for adequate levels.

Deficiencies of vitamin D may have worsened in recent years as more people became aware of the risks of skin cancer and aggressively avoided sun exposure or used sunscreen lotions on themselves and their children. Experts still agree that a fairly modest amount of sun is enough - perhaps 10 to 15 minutes of exposure on your arms and face about three times a week.

Alternatively, you can also get vitamin D from some foods, including vitamin fortified milk and some cereals or breads - assuming you don't have a diet rich in oily fish. For higher levels, supplements are usually necessary.

Among the recent findings and observations about vitamin D:

• Vitamin D is a fat-soluble vitamin that functions as a hormone in the body, regulating calcium metabolism.
• Most people living above 40 degrees latitude do not obtain enough vitamin D from about mid-November to early March.
• Infants who are exclusively breast-fed, and are not supplemented with vitamin D, are at high risk of vitamin D deficiency, because human milk generally doesn't have adequate levels.
• People with dark-colored skin have significantly less ability to synthesize vitamin D from sunlight, as do the elderly.
• Obesity increases the risk of vitamin D deficiency because obese individuals cannot easily access the vitamin D stored in body fat.

So if adequate levels of vitamin D are critical to your health, how much is enough?

The Linus Pauling Institute recommends that generally healthy adults take 2,000 IU (50 mcg) of supplemental vitamin D daily. Most multivitamins contain 400 IU of vitamin D, and single ingredient vitamin D supplements are available for additional supplementation. Additionally, at least 10 to 15 minutes of sun exposure on the arms and legs, or face and arms, at least three times weekly, between 11 a.m. and 2 p.m. during the spring, summer and fall may help Pacific Northwesterners avoid vitamin D deficiency at the end of winter.

"There's a lot we still have to learn about this micronutrient, but it's already clear the role it has in optimal health, and that a lot of people don't get enough," Drake says. "Many people may need to consider supplements, especially in winter. And one thing we would say is, don't be afraid of getting at least a little sunshine. It's good for you."

Source: The Linus Pauling Institute at Oregon State University at lpi.oregonstate.edu.