Too Little Vitamin D May Mean More Colds and Flu

ByABC News
February 23, 2009, 5:23 PM

Feb. 24 -- MONDAY, Feb. 23 (HealthDay News) -- Forget the apple. The largest study of its kind to date shows that vitamin D each and every day is what will keep the doctor away when it comes to the common cold or the flu.

The finding is based on an assessment of vitamin D levels, nutritional habits and respiratory infection rates among nearly 19,000 American men and women.

"We don't want to jump ahead of ourselves," said study author Dr. Adit Ginde, an assistant professor of surgery in the division of emergency medicine at the University of Colorado Denver School of Medicine. "But our study provides support that lower levels of vitamin D are associated with an increased risk for respiratory infections, such as the common cold and the flu. And people who have pre-existing respiratory disease -- like asthma an emphysema -- appear to be at an increased risk for this association."

Ginde's team, from Harvard Medical School and Children's Hospital Boston, reports its findings in the Feb. 23 issue of the Archives of Internal Medicine.

Vitamin D can be found in such foods as canned tuna, cereal and fortified milk or juice, according to the American Dietetic Association (ADA). The body can also be triggered to naturally produce vitamin D after adequate exposure to sunlight.

In addition to its well-established role as a calcium builder and bone fortifier, vitamin D has recently been touted as having a protective role against both colon cancer and multiple sclerosis, the ADA noted.

And in December, a review of studies conducted by researchers at the Mid-America Heart Institute in Kansas City suggested that those with vitamin D deficiency -- a designation estimated to include about half of American adults and nearly one in three children -- might face an increased risk for heart attack and stroke.

To gauge the specific relationship between vitamin D and respiratory risk, Ginde's team analyzed data from the Third National Health and Nutrition Examination Survey, collected from 1988 to 1994.