Vitamin D may help ward off influenza infections during the winter. Grandma always used to administer cod liver oil to keep the family healthy during flu season. Many health professionals relegated this quaint practice to folk medicine at best and an old wives’ tale at worst.
Now Japanese scientists have shown that vitamin D supplements seem to protect school children from seasonal influenza A. 334 children between the ages of 6 and 15 were randomized to receive either 1200 International Units of vitamin D 3 daily or a placebo for four months.
The children getting vitamin D were much less likely to come down with the flu compared to those on placebo. The investigators note that vitamin D3 is crucial for the body to produce key anti-viral peptides such as defensin, which are essential for immune response. Although children with asthma did not get the same protection against influenza A, they were less likely to have a wheezing episode if they were in the Vitamin D group. The authors conclude that vitamin D3 supplementation during the winter might reduce the likelihood that children will come down with type A influenza.
[American Journal of Clinical Nutrition, May, 2010]