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Professor Vieth and the vitamin D era

Posted on: May 14, 2012   by  John Cannell, MD


Historians will debate what started the vitamin D era, what paper triggered it, what scientists discovered its remarkable properties, what groups extolled it and what exactly changed people’s mind from initially believing that vitamin D was toxic to believing it was healthy to take 5,000 IU/day. For me the question is easy. In the year 2001, I read a paper that changed my life. It was not even a new discovery or a new finding. Instead, it was a review paper written by Professor Reinhold Vieth of the University of Toronto and published in 1999. It is free to download in its entirety.

Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am J Clin Nutr. 1999 May;69(5):842-56.

I can remember reading it, thinking, rereading it, and thinking some more, perhaps as many as ten times. Professor Vieth filled the paper with well-established facts. For example, if you go out in the sun naked in the summer around noon and turn slightly pink, you make as much as 20,000 IU of vitamin D.

Those facts led me to the simple question of “Why.” Why so much so fast? Why would nature make such a system that made so much so fast? I thought and thought and read and read and the only answer I could come up with was, “Probably for a good reason.” That’s not much of an answer in light of what we know today, but it was good enough to start the Vitamin D Council, and it was good enough to realize that my life’s work was to spread the word. With sickness in the pit of my stomach, I feared that modern medicine had made a terrible mistake in labeling vitamin D toxic, and thus severely limiting the amount in foods and supplements. I also realized that when science makes a great error, great good is waiting around the corner, if someone can correct that error.

Almost every day the answer, “probably for a good reason,” sounds dumber and dumber. We are rapidly finding out the real answers. Every day another scientist publishes a study showing benefits from everything from pediatric cardiomyopathy (infantile heart failure) to hepatitis C to asthma. Nature gives humans such doses of vitamin D from the sun because vitamin D is the only known building block of a potent substance that functions as the “repair and maintenance” steroid hormone of the human body.

However, Vieth’s paper did something else: it convincingly argued that our fear of vitamin D toxicity verged on hysteria and had nothing to do with science. He meticulously researched all the old publications that claimed vitamin D was toxic only to discover a house of cards, papers that referred back to each other and not to any actual scientific papers showing toxicity. That is, he elegantly exposed that 10,000 IU/day could not be toxic (not if we make that much and more from the sun) and that toxicity more likely starts somewhere well above 20,000 IU/day.

3 Responses to Professor Vieth and the vitamin D era

  1. [email protected]

    Thank you, Dr. Cannell. I appreciate your dedication to quality information regarding Vitamin D3. The Vitamin D Council is a wonderful resource. Please keep up the great work.

  2. RainyDayTreat

    “Almost every day the answer, “probably for a good reason,” sounds dumber and dumber.”

    That isn’t a dumb answer at all. When nature does something for us and we don’t understand why, the best answer in the world is, “probably for a good reason.”

  3. Rita and Misty

    Dr Cannell,

    Agreed: when science makes a great error, great good is waiting around the corner, if someone can correct that error….

    We can correct that error…all of us here, working together…we just need to circle around and hit ’em again (and again and again, if necessary…I’m relentless 🙂 )

    Be well,

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