Fighting A Cold? Try A Little Sunshine!

By Jennifer Brown

Rethink orange juice and lozenges infused with vitamin C for staving off colds and the flu. Perhaps the answer is in the sunshine.

Vitamin D — which can be had for free from the sun's rays — boosts immunity, according to the largest and most nationally representative study so far on the subject.

"The major source of vitamin D is sunlight," said Dr. Adit Ginde, a University of Colorado-Denver surgery professor and lead author of the study, done in conjunction with Harvard Medical School. "That's one potential reason that we have so many respiratory infections in the winter."

The study examined vitamin D levels in the blood of 19,000 people. Those with the lowest levels of the vitamin were about 40 percent more likely to have had a recent respiratory infection.

Still, the study authors said clinical trials must confirm their results before vitamin D is recommended to prevent colds and flu.

Vitamin C has long been associated with boosting immunity against upper-respiratory infections, including colds and flu. But little scientific evidence actually supports that, doctors said.

"It gets out in the lay public and just gets self-perpetuated," Ginde said. "It's one of those things that people say it doesn't hurt to take more. But the science surrounding Vitamin D has really expanded over the last couple of years."