Vitamin D deficiency linked to more colds and flu

Scientific American reports:

Is sunshine more than just a home remedy for a cold? New research suggests it may be: In a study that will be published tomorrow, people with low levels of vitamin D — also known as the "sunshine vitamin" — were more likely to catch cold and flu than folks with adequate amounts. The effect of the vitamin was strongest in people with asthma and other lung diseases who are predisposed to respiratory infections.

People with the worst vitamin D deficiency were 36 percent more likely to suffer respiratory infections than those with sufficient levels, according to the research in this week's Archives of Internal Medicine. Among asthmatics, those who were vitamin D deficient were five times more likely to get sick than their counterparts with healthy levels. And the risk of respiratory infection was twice as high among vitamin D-deficient patients with chronic obstructive pulmonary disease (COPD) than in lung patients with normal levels of the vitamin.

An article well worth your time.