Vitamin D was not helpful in reducing the number of upper respiratory tract infections such as colds or flu. The New Zealand researchers recruited more than 300 healthy adults to get either vitamin D or placebo monthly. The first two doses were 200,000 international units each, and subsequent doses were 100,000 IU for the rest of the 18-month study. This supplied more than five times the US RDA for vitamin D. This dose ensured that those getting vitamin D pills had blood levels of at least 48 ng/ml. There was, unfortunately, no statistical difference in the number of colds and flu infections between the two groups. There were also no side effects.
[Journal of the American Medical Association, Oct. 3, 2012]

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  1. JB

    It’s almost like a painfully humorous sitcom at this point, watching something so embarrassingly stupid that you have to change the channel. How about we set up a parody of “America’s Got Talent” and we’ll let the audience judge which researchers actually deserve funding, no pharma advertising allowed.
    So we know what from this study’s abstract? That in ALREADY healthy people, who ALREADY have higher than the average low/deficient D3 levels of the general population, who already DON’T suffer enough from cold symptoms to call in sick to work, call in to work less often, but not less often enough to be what someone calls statistically significant because they already healthy.
    And how many adults do we know who call in sick because of a stuffy nose and a sore throat? Great . . . I hope my tax money didn’t pay for this. How about seeing if people with LOW D3 levels benefit, aren’t we all supposed to be concerned with making the SICK healthier to save our economy? Oh yeah, if the journalists read the study, the participants were all allowed to have been taking multivitamins on their own with 600 D3 daily IU, and no apparent tracking information re: sun or tanning bed exposure. Paaalease!

  2. HN

    Thank you DS for that information! Even here in the “Sunshine State,” for my city in Central Florida, the altitude is only above 50 for three hours in the middle of the day today. But at that time of day, the “experts” all warn everyone here to put plenty of sunscreen on, which blocks the UV rays needed to make vitamin D. So I’ll keep taking my 6,000 IU a day and not worry about getting enough sunshine to get a valuable amount of vitamin D.

  3. Lise

    Perhaps the study was NOT using D3, the best form. And I doubt seriously they did. Anything to discredit a natural remedy.

  4. HN

    From all that I’ve read on the vitamin D3 studies from the experts whom I follow, this study’s 48ng/ml is just not high enough to prevent colds and flu or possibly prevent cancer. The level that I’ve read that it takes for the real immune system benefits is in the 70-something range. So I take 6,000 IU a day to get me to 72ng/ml, but everyone has a different requirement to get to that 70 to 80ng/ml range.

  5. DS

    One study doesn’t prove that it doesn’t help. After reading about Dr. Cannell’s experience in the Atascadero hospital, my husband and I started taking Vitamin D. I ALWAYS used to be very sick in February. That year, it didn’t happen. It hasn’t happened since. We don’t get the flu shot anymore and although we do get a cold rarely, we have not had the flu and in general we are much healthier. We now take 5000 IU in the warm months and 10,000 IU when the sun can not supply Vitamin D. I check it on the US Naval azimuth table.

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