Vitamin D to Prevent Flu in School Children

Matt (thanks!) sent me the article Flu Season Secret Weapon: Vitamin D To The Rescue. I got a copy of the original paper (1) and here is the deal:

Children in Japan, average age of about 8 to 12, were given 1,200 IU of vitamin D3 or placebo for 4 months and the cases of flu and other symptoms were measured. Children getting vitamin D had 42% less cases of influenza A (.58, .34 – .99). The effect of vitamin D was stronger among kids who had started school later, indicating the ones who started school earlier had built up better immunity.

A reduction in influenza A was not seen in kids who had asthma, although asthma attacks were reduced in those receiving vitamin D by a whopping 83% (.17, 0.04 – .73).

Cases of influenza B did not differ between the two groups, possibly due to different defense mechanisms for preventing influenza A versus B.


1. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010 May;91(5):1255-60. Epub 2010 Mar 10. Link.

6 Responses to “Vitamin D to Prevent Flu in School Children”

  1. radioactivegan Says:

    Do you think the same benefit would be seen with vegan alternatives to D3, such as D2?

  2. Jack Norris RD Says:


    I have not seen anything to indicate that vitamin D2 does not achieve the same results as vitamin D3, but I haven’t seen much comparing their health outcomes.

  3. Tamara Says:

    Thanks Jack. Do you have a suggestion for finding a vitamin D supplement that is vegan and that a 5 year old can take (ie, not a swallow-able pill, but something liquid that doesn’t taste terrible, or chewable)? I found these on Amazon but can’t tell if they are vegan or just vegetarian…

    I have been meaning to up my own and my son’s vitamin D intake (beyond our multivitamin level) after reading another of your articles about a month ago…

  4. Jack Norris RD Says:


    The one you linked to doesn’t say if it’s D3 or D2. But this one appears to be vegan:

    Kal Peppermint Chewable Vitamin D2 1,000 IU

  5. Tamara Says:

    Thanks Jack! That looks like it will work. 🙂

  6. CAB Says:

    This is a D3 from mushrooms.

    Which mushrooms? The USDA National Nutrient
    Database was recently updated to incorporate the
    vitamin D content of nearly 3,000 food entries, including
    mushrooms. The top three selling mushroom varieties
    (white button, crimini and portabella) have vitamin D
    ranging from 1 to 97 percent of the Daily Value (400 IU)
    per raw 84 gram serving.

    How do they do it? Similar to the way that humans
    absorb sunlight and convert it to vitamin D, mushrooms
    contain a plant sterol–ergosterol–that converts to
    vitamin D when exposed to real or simulated sunlight.

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