Tuesday, December 16, 2008

Vitamin D, Flu and the Immune System: Part 2

We now have the answer to preventing the next flu pandemic. This is the second part of the blog on flu. See the first for the background information.

Dr. John Cannell and his colleagues wrote a remarkable paper[1] showing that cold and flu outbreaks are almost completely seasonal. In the northern hemisphere, they occur in December through March. In the southern hemisphere, outbreaks occur June through September—almost exclusively in winter in both hemispheres. The outbreaks of flu and colds in each case occur in times of lowest UVB light and therefore the time of least vitamin D production. It follows then, that essential cathelicidin production is also extremely low during winter, which dramatically dampens the immune response. It would stand to reason, if the theory is correct, that flu and cold outbreaks would occur mainly in winter in both hemispheres. It also stands to reason that increasing vitamin D blood levels by supplementation would be able to reduce the incidence of colds and fly in winter. This is exactly the case.

Shortly after this paper’s publication, other researchers reported results of a three-year study of African-American women.[2] One group was given a placebo and another group received 800 IU per day for two years and 2,000 IU during the third year. The placebo group experienced three times as many cold and flu cases as those who received 800 IU. The 2,000-IU group had only one cold or flu case the entire year, and none in winter. The placebo group had 24 cases in winter—that is a 24:0 ratio!

These findings are especially important because flu shots are not very effective. A review in the British Medical Journal came to the following conclusion: “Evidence from systematic reviews shows that inactivated vaccines [flu shots] have little or no affect on the effects measured.”[3] Perhaps flu shots do save some lives, but there is little doubt that vitamin D does a profoundly better job. Considering that daily supplementation with 2,000 IU per day of vitamin D can cost as little as $10.00 per year, a tremendous financial burden could be lifted from the health-care system and from the budget of elderly persons!

Approximately 36,000 people die yearly from flu in the USA, and it is estimated that a pandemic similar to the one in 1918 could kill a billion people worldwide. It simply does not need to happen. The solution: maintain higher vitamin D levels. This can be done during winter by vitamin D3 supplementation of at least 2,000 IU, and as much as 5,000 IU per day in the absence of UVB exposure. Do not use vitamin D2; it is not nearly as effective.

The flu season is upon us. This year, work to maintain adequate vitamin D levels and kiss the flu goodbye!

[1] Cannell, J. et al. Epidemic Influenza and vitamin D. Epidemiol Infect 2006;134:1129-40.
[2] Aloia, J. et al. Colds and Flu. Letter to the editor. Epidemiol Infect Jan 15, 2007.
[3] Jefferson, T. et al. Influenza vaccination: policy versus evidence. BMJ. 2006;333::912-15.

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