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Vitamin D — Minimum, maximum, optimum: Conference overview

Posted on: October 25, 2012   by  Dr William Grant


A vitamin D conference, “Vitamin D — Minimum, maximum, optimum” was held in Warsaw, Poland, Oct. 19-20, 2012, to develop guidelines for vitamin D for Central Europe. It was organized by Pawel Plodowski and Elzbieta Karczmarewicz. There were 550 attendees from Poland and other countries. The international scientific committee included:

  • Belorussia (Ema Rudenka and Ludmila Yankovskaya)
  • Canada (Glenville Jones)
  • Germany (Berthold Koletzko)
  • Hungary (Tamas Decsi)
  • Israel (Yehuda Shoenfeld)
  • Poland (Twenty-seven members)
  • Switzerland (Heike Bischoff-Ferrari)
  • The Ukraine (Vladyslaw Povoroznyuk)
  • The UK (Graham Carter and Elina Hypponen)
  • The United Arab Emirates (Afrozul Haq)
  • The United States (Michael Holick and me)

Many other countries were represented including Australia, Finland, Kenya, Norway, Russia, and Scotland. Several dozen posters were also presented.

Non-skeletal effects including autoimmune diseases including multiple sclerosis and rheumatoid arthritis, cancer, diabetes mellitus, cardiovascular disease, chronic kidney disease, diabetes mellitus, immunity, musculoskeletal defects, rickets and adverse pregnancy outcomes were discussed. Adverse effects of high serum 25-hydroxyvitamin D [25(OH)D] were discussed with the conclusion that there is little verified evidence of harm below a daily intake of 10,000-20,000 IU/d vitamin D3 or serum 25(OH)D concentrations above 100 ng/ml. Graham Carter of DEQAS (Vitamin D External Quality Assessment Scheme) discussed the accuracy of 25(OH)D assays worldwide.1 Papers by many speakers were published in two Polish journals, Standardy Medyczne/Pediatria (Standards of Medicine/Pediatrics) 2012;9(5): and Postepy Nauk Medycznych (Progress in Medicine) 2012;XXV(3). Henry Lahore is making many of the papers available at www.vitamindwiki.com in html format, which permits translation into any of 57 languages.

The committee included consideration of observational studies in addition to randomized controlled trials (RCTs), a significant contrast to the Institute of Medicine (IOM) which considered only RCTs and set the recommended 25(OH)D concentration at 20 ng/ml. Although Glenville Jones made the case for the IOM position here, that proposal received very little support from the scientific committee or others at the conference.

The primary recommendation was that the 25(OH)D concentration should be between 30-60 ng/ml. A paper by Lorenc et al. [2012] suggested the range be set at 30-80 ng/ml, but the conference decided there is a lack of evidence for higher concentrations for the time being. Committee members voted on many issues prior to the meeting, with the results presented at the end of the conference.

Given the care in assembling a scientific committee with a number of the world’s leading vitamin D researchers, the recording of the presentations, the publication of speakers’ reviews, and the very large attendance, the recommendations from this conference should be considered and receive widespread acceptance.

As an aside, the reason that the IOM considered only RCTs is that they were following the principles of evidence based medicine. I prepared a paper for this conference that applied Hill’s criteria for causality to vitamin D and cancer .4 Many factors and studies can be considered with such criteria. You can read his original paper in its entirety.

For those interested in some of the short-comings of evidence based medicine, see Tarnished Gold, the Sickness of Evidence Based Medicine by Steve Hickey and Hilary Roberts, published in 2011. I believe that the Hill criteria are more suitable for public health recommendations than those relating evidence based medicine based primarily on RCTs.


  1. Carter G. 25-hydroxyvitamin D assays; the stare we’re in. Standardy Medyczne/Pediatria. 2012;9:675-9.
  2. Lorenc RS, Karczmarewicz E, Kryskiewicz E, Pludowski P. Vitamin D provision and supplementation standards. Standardy Medyczne/Pediatria. 2012;9(5):595-604.
  3. Hill AB. The Environment and Disease: Association or Causation? Proceedings for the Royal Society of Medicine, 1965;58:295-300. (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1898525/)
  4. Grant WB. A review of the evidence regarding the solar ultraviolet-B–vitamin D–cancer hypothesis. Standardy Medyczne/Pediatria. 2012;9:610-9.

4 Responses to Vitamin D — Minimum, maximum, optimum: Conference overview

  1. [email protected]

    I am disappointed.

    Given the multitude of diseases linked to Vitamin D deficiency/insufficiency, and the conclusion that there is little verified evidence of harm below a daily intake of 10,000-20,000 i.u./daily or serum 25(OH)D concentrations above 100 ng/ml, it is infuriating to me that the committee recommends the narrow range of 30-60 ng/ml as sufficient.

    Don’t get me wrong. I do think this is MUCH better than what the Institute of Medicine recommends (20 ng/ml). However, it is IMO still not high enough.

    I know from my own health issues, the benefits of Vitamin D didn’t take effect for me until my blood levels reached around 85 ng/ml.

    Really, the range should be between 30 ng/ml—100 ng/ml, with levels determined on a patient-by-patient basis.

    And that is my 2 cents worth….


  2. Dr William Grant

    Sorry to learn that you are disappointed. I, on the other hand, was delighted. You have to understand that this recommendation is for the general population and is based on the evidence available largely from observational studies and randomized controlled trials, and is meant to reduce the risk of adverse health outcomes. What you seem to be concerned with is treatment of a health condition for a particular individual. This is generally done in consultation with a physician who will have serum 25(OH)D concentration measured. Since the 85 ng/ml is below 100 ng/ml, your physician would have no trouble approving that concentration. Unfortunately, there have been no randomized controlled trials with 10,000 IU/day or observational studies with people with serum 25(OH)D concentrations near 85 ng/ml, and there are some studies reporting adverse effects above 30 or 40 ng/ml (flawed studies in my opinion), so that health policy officials tend to err on the side of caution.

  3. theguru

    Is there any way out from the connection between vitamin D levels and vitamin D intake?

    I mean, we are meant to MAKE vitamin D, not to TAKE it.

    The discussion about different levels of serum 25(OH)D concentration seems to be closely related to the risk of adverse health outcomes from oral vitamin D supplementation, not from UVB-exposure.

    By adopting the principle of getting ones vitamin D from UVB exposure, I assume the discussion about safety for any level in the blood will become less relevant since the human body has a built in system to handle the risk of over-dose?

  4. Dr William Grant

    There is considerable variability between oral intake and serum 25(OH)D concentrations. This is shown in the graph on the home page of http://www.grassrootshealth.net. However, as one’s 25(OH)D concentration increases, hydroxylation of vitamin D to 25(OH)D decreases, thereby being one mechanism to limit 25(OH)D from oral intake. Solar UVA can destroy vitamin D and its metabolites, so one cannot get 25(OH)D concentrations that are too high from UV irradiance. Given modern lifestyles, supplements are an important source of vitamin D.

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