Breaking news-Vitamin D prevents Asthma and Influenza

Placebo controlled trial demonstrates Vitamin D supplements dramatically reduce influenza infections and asthma attacks

This week a study published in the American Journal of Clinical Nutrition provided convincing data that demonstrated Vitamin D can help the body ward off viral infections and asthma attacks. More than 600 Japanese schoolchildren aged 6-15 were treated from December 2008 through to the end of March 2009 with Vitamin D (1200 IU per day) or placebo (1).

The number of infections with the viruses influenza A and B and the number of asthmatic attacks were assessed. Of note is the fact that influenza A includes the H1N1 strain that was responsible for the pandemic alerts of last year.

Whether a child had succumbed to influenza over the course of the study was confirmed microbiologically using swabs from the nose/throat.

Those children taking Vitamin D developed 42 percent fewer infections with influenza B. The benefits were even more dramatic in children who had not been previously supplementing with Vitamin D, and in these children there was a 64 percent reduction in the infection rate.

Perhaps even more interesting was the reduction in the number of children developing asthma attacks. Those children taking Vitamin D supplements had a six-fold reduction in the number of asthma attacks. This difference was found to be highly statistically significant P<0.006) .

In summary, this is a placebo controlled trial--the gold standard of clinical research-- that demonstrated up to a 60% reduction in the incidence of viral infections and a six-fold reduction in the incidence of asthma attacks.

Also of note is the fact that the dose of Vitamin D3 used, only 1200IU, is low compared to the current recommendations of Vitamin D experts. In addition, the clinical trial only ran for three months. We know that it can take many months of supplementation to improve Vitamin D levels. Although actual Vitamin D levels were not measured in this study, the relatively low dose used and short study duration would suggest that many of the children would not have reached anywhere near optimal levels of Vitamin D during the trial. Still,the results were dramatic.

Last month we reported two studies that demonstrated Vitamin D deficiency was associated with severe asthma and declining lung function in asthamatics. (link) In addition, preclinical data was reported suggesting that Vitamin D could dramatically reduce the need for steroids in asthma patients. (link)

These data indicate that maintaining optimal levels of Vitamin D will significantly reduce the incidence of asthma attacks, prevent gradual decline in lung function and reduce dependency on steroids.

References:
1. Urashima M, et al. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr 10th March 2010.