Vitamin D Might Protect Against H1N1 Flu

2009-08-28 13:39

The Public Health Agency of Canada (PHAC) has teamed up with researchers from various institutions and hospitals to investigate the role vitamin D may play in protecting against the H1N1swine flu virus. This is a new direction for an ongoing study that the agency started last year to determine the role vitamin D may play in severe seasonal flu.

Reports of this study come on the heels of a statement about the swine flu from the President’s Council of Advisors on Science and Technology on August 24, which said that 1.8 million Americans could be hospitalized, and about 50 percent of them could die, under a worst-case scenario. The swine flu vaccine may be available by October, but what should individuals do until then? Could taking vitamin D protect against this potentially deadly disease?

Any meaningful analysis of results from the current study by the PHAC will take time, probably at least three flu seasons, according to the agency. Currently the researchers are trying to determine whether there is a correlation between severe influenza disease and low levels of vitamin D and/or a person’s genetic makeup. They are adapting this approach to H1N1 with the hope that it will help prevent serious outbreaks of swine flu infection.


Previous studies show promise that vitamin D may be effective in protecting against swine flu. A June 2009 report in the Journal of Immunology suggests that vitamin D promotes the production of antimicrobial substances that have the ability to neutralize the activity of various disease-causing agents, including influenza virus.

In another study, published in the February 23, 2009 issue of the Archives of Internal Medicine, researchers studied 19,000 individuals and found that those who had lowest average levels of vitamin D (defined as less than 10 ng/mL) were about 40 percent more likely to have recent respiratory infection, including flu, compared to those who had higher levels of vitamin D (30 ng/mL or higher).

According to the most recent data on the status of vitamin D in the US population (2000-2004 NHANES), most Americans have levels less than 30 ng/mL. When looking at the elderly, research shows that more than 50 percent have levels below 20 ng/mL. These figures suggest that the majority of Americans have insufficient levels of vitamin D to help protect against swine flu, should the studies indicate that this nutrient provides this protection. In the meantime, given that most people appear to be deficient in vitamin D and flu season is upon us, it may be prudent to consider supplementation after consulting with a healthcare professional.

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Doss M et al. Journal of Immunology 2009 Jun 15; 182(12): 7878-87
Ginde AA et al. Archives of Internal Medicine 2009 Feb 23; 169(4): 384-90
Gordon CM et al. Archives of Pediatrics & Adolescent Medicine 2008 Jun; 162(6): 505-12
President’s Council of Advisors on Science and Technology, report assessing H1N1 preparations

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