Having too little vitamin D can pose risks to health

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.

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.

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.

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."

Tammie Smith can be contacted at TLsmith@timesdispatch.com.