QUICK STUDY: A digest of new research on major health topics
Sunshine vitamin may offer some protection.
THE QUESTION Some believe that Vitamin D, the nutrient most often linked to calcium and the maintenance of strong bones, might also help prevent colds. Is such a belief grounded in fact?
THIS STUDY analyzed data on 18,883 people, age 12 and older, including tests that measured levels of Vitamin D in the bloodstream. About 19 percent reported having had a cold within a few days of their starting the study. People with the lowest levels of Vitamin D (less than 10 nanograms per milliliter of blood) were 36 percent more likely to have had a recent cold, regardless of the time of year, than were those with the highest levels (30 or more nanograms). Risks were greater for people with asthma and low Vitamin D levels; they were five times more likely to have had a cold than those with the most Vitamin D.
WHO MAY BE AFFECTED? People with low levels of Vitamin D, which the body takes in through exposure to sunshine (15 minutes several times a week is recommended) and from food (egg yolks, saltwater fish, liver and fortified milk) or supplements. Most people need the equivalent of 400 to 600 international units of Vitamin D daily.
CAVEATS The study did not prove that low levels of Vitamin D cause colds; it could be that Vitamin D levels drop when someone has a cold.
FIND THIS STUDY Feb. 23 issue of Archives of Internal Medicine.