Vitamin D levels and viral illness

The Buzz: Raising serum 25(OH)D3 levels above 38 ng/ml may significantly reduce susceptibility to viral respiratory illness
Citation: Sabetta JR et al. "Serum 25-hydroxyvitamin D and the incidnece of acute viral respiratory tract infections in healthy adults." PLoS ONE 5(6):e11088 June 2010
Summary: This past winter, researchers at Yale University prospectively measured serum 25(OH)D3 concentrations in 198 healthy adults and tracked the incidence of acute respiratory tract infections, reporting a two-fold reduction in risk of developing infection for those with concentrations > 38 ng/ml.
Commentary: A high quality (blinded, prospective) trial which suggests a new way to reduce the burden of viral respiratory illness. A better study design would be placebo-controlled, but these findings are suggestive of a benefit.
By: Spencer Blackman MD