Vitamin D3 Reduces Flu, Asthma in Kids

TOKYO, JapanVitamin D3 supplementation during the winter may reduce the incidence of flu, especially in specific schoolchildren who were not taking other vitamin D supplements, according to a new study published in the American Journal of Clinical Nutrition (2010 Mar 10). Additionally, they found vitamin D3 supplementation was also associated with fewer asthma attacks in children.

From December 2008 through March 2009, Japanese researchers conducted a randomized, double blind, placebo-controlled trial comparing vitamin D3 supplements (1,200 IU/d) with placebo in schoolchildren. Among the children, they recorded the incidence of influenza A, diagnosed with influenza antigen testing with a nasopharyngeal swab specimen.

Influenza A occurred in 18 of 167 (10.8 percent) children in the vitamin D3 group compared with 31 of 167 (18.6 percent) children in the placebo group (P = 0.04). The reduction in influenza A was more prominent in children who had not been taking other vitamin D supplements (P = 0.006), and who started nursery school after age 3 years (P = 0.005).

In children with a previous diagnosis of asthma, asthma attacks occurred in two children receiving vitamin D3 compared with 12 children receiving placebo (P = 0.006).