Vitamin D does not prevent colds or infections, study finds

If you’re trying to ward off the sniffles, you can take vitamin D supplements out of your shopping cart: A new study reports that dosing with the vitamin does nothing to prevent colds or other forms of upper respiratory tract infections (URTI).

The effect of vitamin D on the immune system has been debated for a long time. Controlled laboratory research has shown that vitamin D has several beneficial effects on the immune system, and some studies conducted in the past have suggested that people with low levels of the vitamin are at higher risk for URTIs. But the authors of the new study, published Tuesday in the Journal of the American Medical Assn., point out that the previous studies were poorly controlled and results have been mixed, calling into question whether the vitamin does anything at all for URTIs.

To answer the question, the researchers, who are based in New Zealand, conducted a randomized trial nicknamed VIDARIS, for “Vitamin D and Acute Respiratory Infection Study.” They gave 161 subjects doses of vitamin D once a month for 18 months, and another group of 161 people a placebo. The doses used were those that appeared to have been the most effective against colds in previous studies.

Over the 18-month period, the vitamin D group reported 593 URTI episodes, while the placebo group reported 611 -- an insignificant difference that is likely due to chance, the authors wrote. There were also no differences between groups in days of work missed, or severity of symptoms. In healthy adults at these recommended doses, Vitamin D appeared to have absolutely no ability to reduce the impact of colds.

In an accompanying editorial, Dr. Jeffrey Linder of Harvard Medical School says the study is well-conducted and its results should be trusted. “The VIDARIS trial, which assessed upper respiratory tract infections as they actually occur in the real world, demonstrated that vitamin D supplementation does not reduce the incidence of respiratory tract infections in adults,” he wrote.

That means you can probably stash away your vitamin D pills wherever you put your Airborne.

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