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Prenatal vitamin D supplementation did not improve child respiratory health

Posted on: July 8, 2013   by  Vitamin D Council


In a new randomized controlled trial, researchers have found that low dose vitamin D supplementation during pregnancy had no effect on their children’s respiratory health in early childhood.

Past research has shown that, for adults, low vitamin D levels are associated with an increased risk of respiratory disorders.  Additionally, researchers report that vitamin D supplementation may decrease the burden of respiratory infections.

Stephen Goldring, MD, at the Department of Pediatrics of Imperial College London, and colleagues conducted a follow up study of the children of women who were participants in a randomized controlled trial using vitamin D supplementation during pregnancy.

Participants in the original trial included women who were 27 weeks pregnant and either Asian, Middle Eastern, African American, or Caucasian. The women were randomized to 800 IU vitamin D2 daily until delivery, single oral dose of 200,000 IU vitamin D3, or no treatment.

The researchers report that median umbilical cord vitamin D levels at delivery were significantly lower in the control group (7 ng/ml) compared to the daily dose group (10.5 ng/ml) and the large one time dose group (10 ng/ml). They found no difference in the appearance of wheezing, prevalence of eczema (skin irritation), allergies, or lung function between the three groups. The authors found increased asthma medication use and a higher prevalence of lower respiratory infections in the offspring of those in the large one-time dose group.

The authors do offer an explanation for these findings. “…supplementation with vitamin D only started at 27 weeks of gestation. It is known that immune cells develop much earlier in fetal life, and that airway development to the respiratory bronchioles is complete by 16 weeks gestation. It may be that supplementation earlier in pregnancy, or indeed pre-conception, is necessary for protection against childhood wheezing.”

Given the slim effect vitamin D had on cord blood levels, the authors recommend future studies explore the safety and efficacy of higher dose vitamin D supplementation. There are some trials in this realm currently underway.


Prenatal vitamin D supplementation and child respiratory health: A randomized controlled trial. PLOS ONE, 2013.

10 Responses to Prenatal vitamin D supplementation did not improve child respiratory health

  1. [email protected]

    A recent study showed no effect in reducing knee pain when supplementing 2000iu vitamin D. That certainly was true for my wife and I but when we began taking 5000iu plus daily for over 6 months, we both noticed a remarkable improvement. My point is many studies may very well be using doses too low to show positive results. I suspect current recommendations for pregnant women to take 4000iu daily could have better outcomes.

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  2. Debbie

    800 IU? Bad science. Bad study. Bad medicine. And the media will run with this. So sad.

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  3. John

    The Drs in the study felt confident that a 200,000 IU single dose of D3 would not harm the pregnant mother and her baby!!! That’s big news.

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    • Brant Cebulla

      I’m surprised at how low the cord blood was even in the 200,000 IU group (10 ng/ml). Surely if vitamin D during pregnancy does have an effect on childhood respiratory health, cord blood needs to be much higher than 10 ng/ml. Just shows how high the vitamin D requirements might be for pregnant women.

      I know there are a few studies underway examining this same question — does vitamin D during pregnancy affect childhood respiratory health? The Wagner/Hollis group are following the children out of their 4000 IU/day during pregnancy RCT. There was also an RCT in the Midwest (can’t think of the name at the moment) looking at this, too, using similarly high doses.

  4. IAW

    I have been a member a long time. I read everything that is added to both the news and the blog. At this point, with everything the Vitamin D Council knows, just exactly what were we suppose to take away or learn from this news story above. I really do not even understand why it was included at all.
    First of all you should have named it “Lower doses of Prenatal Vitamin D supplementation…” Next, I think there should be a “rebuttal” by the VDC that says something to the effect that “We here at the VDC feel that only D2 should be used for humans, that D3 should be given in daily doses and that the amount of Vitamin D3 in this study should have been a minimum of 5000 iu (or 6000 iu) before any benefits might possible have been had.”
    If I was brand new to this website this morning and read this article, what would it say to me? What information are you hoping to impart?

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    • Brant Cebulla

      If you did a literature search on vitamin D, you’d actually find a handful of “no-finding” research, where vitamin D didn’t correlate with a disease or supplementation didn’t help a disease. We have a choice — to either ignore it and not report it, or we can report it.

      Over the past few years, we’ve done a ton of surveying and usability testing. We’ve found that people want us to report on it. Furthermore, we’ve found that health care providers don’t give our organization much credence unless we do report on “no-finding” research. Unlike laymen, they do have the skill set to do literature searches, so ignoring particular research really doesn’t sit well with them at all.

      If I’m brand new to this website, and I read this article, I’m thinking “Wow, this website seems unbiased, I’m more open to trusting the information they provide.” This is proven by our own internal usability testing. This internal testing also matches well established industry-wide research into the wants and needs of patients/people. People want information from organizations that do not suffer from bias. As a public health group, if we’re any good at what we do, we have to create the perception that we don’t suffer from bias.

      Lastly, you’ll notice in the past couple of years, the times that we do report on no-finding research, this has led to the best discussion, usually generating deep comment threads. This is exactly what we want. We want people to interact, think about vitamin D, critique studies, relay their own thoughts, do their own research. If we’re going to bring better vitamin D awareness to the world, we need to first build an interactive community.


  5. Ron Carmichael

    I respect the notion and desire to “KNOW” what the dosage should be, but the only valid concern for the researchers conducting ANY study regarding the potential effects of vitamin D3 is what the subjects’ blood levels are. Any study subject with a level below 40 (or 50 ) ng/ml is simply proving a negative which the media in general are obviously ill prepared to comprehend the significance of. Achieve a mother-nature blood level around 50 ng/ml (no matter what the daily dosage is), and THEN conclusions are far more likely to be measurable, reliable, reproducible, verifiable, and yes, even useful. It’s as if we need a category to assign certain studies to, titled “Yet another ill-informed researcher proves that 800iu is totally useless”…

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  6. Rita and Misty

    @Ron Carmichael, we are kindred spirits. I do believe that only the 25(OH)D level is what counts.

    As you know, I choose to keep my level at the higher end of optimal–I have health issues.
    But, I do agree that for most healthy individuals a serum level of 50 ng/ml would be outstanding.

    It depresses me to admit this, but I think it will be a very long time before we see studies administered by blood level rather than dosage. And, an even longer time before studies utilize a level of 50 ng/ml. Let us remember that the IOM has recommended 20 ng/ml as healthy.

    Yes, folks, the media will pick up on this inadequate study, and D will receive a bad rap.

    Change will not occur at solely the individual level, folks. Last year, this time, I thought it would suffice. I no longer believe this to be true. But, today I believe we need a much more united approach to resolve this matter We need to get some large organization(s) to push this cause.

    @JOHN–your link doesn’t work for me, BTW.
    @JOHN–it is an interesting comment you make…

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  7. [email protected]

    Sometimes I read these studies, here and in the literature over the past 40+ yrs, and I can only conclude that the researchers know very little about the subject or, the protocols are set up in a way to satisfy the funding source, i.e. the Industrial Medical Complex, to ensure failure.

    I know conspiracy theories sound attractive but the truth of the matter is that stupidity usually predominates.

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  8. Rita and Misty

    BC–I can assure you it is about the funding.

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