Vitamin D in School Children Reduces Influenza Incidence 1


For a few years now I’ve always taken Vitamin D during the winter and felt it helped reduce the incidence and severity of colds I would get.   Now a study just published shows that giving vitamin D to school children reduced the incidence of influenza.   We should all be having our Vitamin D levels checked, especially if we are one to get a lot of colds each year.    Taking 1000-2000IU/day through the winter may be your best bet if you cannot get your blood tested.   There is almost no risk of developing any toxicity at 2000IU/day, unless you already had high levels of D in your blood.

Background: To our knowledge, no rigorously designed clinical trials have evaluated the relation between vitamin D and physician-diagnosed seasonal influenza.

Objective: We investigated the effect of vitamin D supplements on the incidence of seasonal influenza A in schoolchildren.

Design: From December 2008 through March 2009, we conducted a randomized, double-blind, placebo-controlled trial comparing vitamin D3 supplements (1200 IU/d) with placebo in schoolchildren. The primary outcome was the incidence of influenza A, diagnosed with influenza antigen testing with a nasopharyngeal swab specimen.

Results: Influenza A occurred in 18 of 167 (10.8%) children in the vitamin D3 group compared with 31 of 167 (18.6%) children in the placebo group [relative risk (RR), 0.58; 95% CI: 0.34, 0.99; P = 0.04]. The reduction in influenza A was more prominent in children who had not been taking other vitamin D supplements (RR: 0.36; 95% CI: 0.17, 0.79; P = 0.006) and who started nursery school after age 3 y (RR: 0.36; 95% CI: 0.17, 0.78; P = 0.005). In children with a previous diagnosis of asthma, asthma attacks as a secondary outcome occurred in 2 children receiving vitamin D3 compared with 12 children receiving placebo (RR: 0.17; 95% CI: 0.04, 0.73; P = 0.006).

Conclusion: This study suggests that vitamin D3 supplementation during the winter may reduce the incidence of influenza A, especially in specific subgroups of schoolchildren.


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One thought on “Vitamin D in School Children Reduces Influenza Incidence

  • Cheryl Mandler

    Hi George,

    Interesting article although I’d like to see a larger sample. I had my Vit. d done the same day I had the bone density. It was 38 with normal 40-60. She sent back a letter saying increase to 1000 IU per day. I have been doing that with 3 of those bone growth supplements. Do you think I should take another 1000 iu of just Vit d now or wait until the fall when there is less sun? I made copies of the last two bone densities which I’ll send. The hip was ok but the lumbar continues to get worse closing in on the Osteoporosis numbers. I’m going to ask for exercises for the spine but you generally don’t break anything there–you’re just hunched over which I’m trying to work on. I guess your Mom and Theresa want to see the progress on your house and Max ( and maybe even you and Joy!) so they are coming on the 28th for a few days. This rain has been horrible. We have to spend another 5-7 thousand on french drains for the rest of the basement plus money to redo the walls and floors. Remember how I said homes are great but money pits!!! Cheryl