In a randomized, double-blind, placebo-controlled trial, 1200 IU of Vitamin D was administered to schoolchildren to assess if it reduced the risk of influenza and asthma. There was a 42% reduced risk of influenza in the schoolchildren receiving the Vitamin D and a remarkable 83% reduced risk of ashma of asthma attacks in the children previously diagnosed with asthma. The researchers concluded:
“This study suggests that vitamin D-3 supplementation during the winter may reduce the incidence of influenza A, especially in specific subgroups of schoolchildren.”