Advances

Vitamin D on trial

Pills containing vitamin D are often marketed for their alleged ability to boost the immune system. But a recent randomized, controlled trial led by Geisel assistant professor of community and family medicine Judy Rees found that taking vitamin D did not ward off or minimize the symptoms of upper respiratory tract infections. "Of course there are observational studies that show that vitamin D has various benefits," Rees told the New York Times. "But those studies can't eliminate the effects of lifestyle from causing bias. A randomized trial is designed to avoid those problems, and that's what I think we did."