Vitamin D to Prevent Flu in School Children
Matt (thanks!) sent me the article Flu Season Secret Weapon: Vitamin D To The Rescue. I got a copy of the original paper (1) and here is the deal:
Children in Japan, average age of about 8 to 12, were given 1,200 IU of vitamin D3 or placebo for 4 months and the cases of flu and other symptoms were measured. Children getting vitamin D had 42% less cases of influenza A (.58, .34 – .99). The effect of vitamin D was stronger among kids who had started school later, indicating the ones who started school earlier had built up better immunity.
A reduction in influenza A was not seen in kids who had asthma, although asthma attacks were reduced in those receiving vitamin D by a whopping 83% (.17, 0.04 – .73).
Cases of influenza B did not differ between the two groups, possibly due to different defense mechanisms for preventing influenza A versus B.
1. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 May;91(5):1255-60. Epub 2010 Mar 10. Link.