Now Vitamin D is Bad???

by Marcia Dettloff, OD on December 2, 2010

I’m not an expert but I ‘ve done a lot of research on Vit D and  I have been emphasizing the importance of getting adequate Vit D with all my patients for the past year.  Unfortunately, when the US Institute of Medicine’s Food and Nutrition Board  released their updated dietary recommendations for calcium and Vitamin D yesterday, headlines reported that people are getting too much Ca and Vit D leading many people to think all the recent Vit D hype was just another nutrition fad.

I’ve seen many news reports implying that Vit D is dangerous.  Here’s the  brief of the FNB’s findings.  What the report actually says is that Vit D can cause problems in dosages over 10,000 IU/day.  While I have not seen research indicating problems even at that level, 10,000 IU /day is a much higher dose than is typically recommended except for treatment of severe deficiencies.

There are several comments I would like to make regarding the report and its recommendations.  The main problem is that they only looked at the benefits of Vit D that could be conclusively proven by scientific studies.   Using that criteria, they say that they only found a benefit for Vit D in bone health.

Interest and research into the health benefits of Vit D is a relatively new field.  There are an ever-increasing number of correlational studies and anecdotal reports showing associations between Vit D deficiency and various diseases, but they don’t prove cause and effect like a controlled study does.  While I understand the importance of making recommendations based on controlled studies, totally ignoring the vast number of studies that show a link to Vit D and making only minimal changes to the RDA for Vit D despite the dramatic change in our exposure to UVB since the last recommendations (from 1997) is surprising and disappointing, especially given the safety profile of  Vit D.

Unfortunately large-scale controlled studies cost a lot of money and take time.  Vitamin D is dirt cheap so there’s no incentive for pharmaceutical companies to fund research and government research dollars are few and far between.  Despite these problems, new studies (including some controlled studies)  are coming out on a regular basis.  Given that the committee started it’s evaluation in March 2009 and completed it in March 2010, the report was probably obsolete before it was even published.

The second problem is that once the committee decided that Vit D was only important to bone health,  it assumed that most people are getting adequate levels of Vit D because levels of 20 ng/mL were found to be sufficient for good bone health.  Even though studies may not have proven the benefits of Vit D beyond bone health we know that Vit D turns into the hormone calcitriol and over 2000 genes have been found to have receptors for calcitriol.  We may not know what those calcitriol receptors are controlling yet but it’s highly unlikely that those receptors are just influencing bone health.

In the absence of controlled studies showing benefits, I can understand the committee’s reluctance to endorse high doses of Vit D. I am generally skeptical of the need for supplements in a person that has a good diet and healthy lifestyle.  I assume that we have evolved to do well without distorting our natural diets and the research generally bares that out.  However, the main goal of Vit D supplementation is not to exceed but rather to restore Vit D to natural levels.

Even in the absence of proof that Vit D has protective health benefits, when we KNOW that healthy people who live and work in the sun have Vit D levels between 50-80 ng/mL; that our bodies have the capacity to make 1000 IUs of Vit D a minute in the midday summer sun; that we have had a recent and dramatic decline in exposure to UVB; that toxicity doesn’t occur until Vit D levels reach 200 ng/mL and that Vit D3 supplements cost just pennies a day (and the sun is free) it seems ludicrous to only raise the RDA from 400IUs a day to 600 IUs a day.   To add insult to injury, totally ignoring all research in favor of restoring natural Vit D levels of 50-80 ng/mL and stating that levels of 20ng/mL are adequate paves the way for insurance companies to deny coverage for Vit D testing as was done by Ontario Province in Canada  the day before the report was released.

On a somewhat positive note, the Upper Level Intake (the safe maximum dosage) was doubled from 2000IU/day to 4000 IU/day.  So even in light of their very conservative RDAs that go against the recommendations of all the major experts in Vit D research,  they at least confirm that it is safe to take 4000 IUs a day.

As far back as March 2007 an editorial co-authored by departments of major universities worldwide appeared in the American Journal of Clinical Nutrition, calling for the urgent need for an increase in Vit D dietary reference intakes.  Research linking Vit D deficiency to various diseases has only increased since then.  Hopefully, controlled studies will be forthcoming that can give us concrete answers.   But until or unless research comes out showing negative effects from Vit D supplementation to natural levels, I feel that the potential benefits far out weigh the risks and will continue to educate my patients about the importance of Vit D .   I personally take 4000-5000 IUs of Vit D a day (when I remember)  and, much to their dismay ( I mean delight), my children each received a bottle of Vit D3 in their Christmas stockings last year and will again this year!

If you’d like to learn more about Vitamin D, is the most  comprehensive source of up-to-date information and the latest research that I have found.  Here is a link to the Vitamin D Council’s statement on the FNB Report .


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