Too little vitamin D can pose health risks

By: Tammie Smith | Richmond Times Dispatch
Published: March 28, 2009

Having too little vitamin D can pose risks to health

Q:I'm a 30-year-old female who works in health care. Much to my surprise I was diagnosed as vitamin D deficient at a recent checkup. I've seen vitamin D deficiency with my patients, but now that it has happened to me, I'm baffled. Though I spend a lot of time indoors, I grew up in Florida so am no stranger to the sun. My family is Greek.

Answer: According to research out this week, an increasing number of Americans are not getting enough vitamin D, and a major reason is too little time in the sun.

I attended a community forum on prostate cancer about a year ago and was surprised to hear one speaker say that his regimen for battling prostate cancer included spending more time in the sun. He had read about the benefits of vitamin D and evidence linking vitamin D deficiencies to some cancers.

Sun exposure accounts for most of the vitamin D our bodies make, but it is also in some foods and can be taken as supplements. The speaker at the forum also knew that as an African-American, his darker skin put him at greater risk of being vitamin D deficient.

Low vitamin D levels are a well-known risk factor for rickets, a bone softening in children that can cause bowed legs. More recently, low vitamin D levels have been linked to cardiovascular disease, infections and cancer.

In the study out this week in the Archives of Internal Medicine, researchers compared average vitamin D levels collected during national nutrition surveys from 1988 to 1994 with those collected from 2001 to 2004.

The average serum vitamin D level decreased from 30 nanograms per milliliter to 24 during that period. While a level of 20 used to be considered fine, many experts now think 30 is a better number to aim for.

"Over 30 is good. The high end of the range would be 100. I would rather be in the 50s," said Crista Galvin-Cox, a registered dietitian at Virginia Women's Center.

"We are just not out in the sun the way we used to be," she said. "When we go out, we are so skin cancer conscious, which is what we should be. By putting the sunblock on, that blocks 99 percent of the rays that make vitamin D."

Galvin-Cox is not advocating lavish sunbathing or forgoing sunscreen. Vitamin D supplements can help get levels up. Right now, the recommended daily allowance of vitamin D for adults is 200 to 600 international units -- with the recommended amount increasing with age.

"They are looking at raising that to 1,000," Galvin-Cox said. "Right now, to all my patients I recommend they take 1,000."

Galvin-Cox said a Caucasian person could get enough vitamin D by spending 15 minutes outside during a sunny summer day with arms and legs exposed. A darker-skinned person might need to extend that to 30 minutes.

The American Academy of Dermatology takes the position that it's safer to get vitamin D from supplements instead of sun exposure, which carries the risk of skin cancer.

University of Richmond law professor Jonathan K. Stubbs strikes a balance -- he does not overdo the sun exposure and takes vitamin D supplements.

"I feel strongly about sun exposure and the importance of vitamin D, more specifically vitamin D3 as an important supplement to help the immune system's defense against diseases like prostate cancer," Stubbs wrote in a recent e-mail that described his regimen. "When diagnosed three years ago with early-stage prostate cancer, I was surprised to learn that I had an extremely low level of vitamin D."

For more on vitamin D, the U.S. Office of Dietary Supplements has a fact sheet at: http://ods.od.nih.gov/factsheets/vitamind.asp.

Contact Tammie Smith at (804) 6496572 or TLsmith@timesdispatch.com.