Vitamin D Toxicity? No way!

January 14, 2011

Vitamin D Toxicity 

 Reference: Southern Medical Journal 102(7):765 (2009) Competency:  Vitamin D 

 With all the brouhaha about the IOM information about D, folks have asked what is the toxicity?  As best we know, not much.  But here is the real scoop as I can see it.  First of all, the case study I reference above is about a woman who mistakenly took 150,000 IU a day for some 28 years without any toxicity.   The article has a very nice discussion about possible mechanisms how that happened.  

I’ve personally witnessed someone taking 1,000,000 IU in one dose with no apparent symptoms.  And I personally know of someone who took 50,000 IU a day for over a year with no symptoms.  But those are just anecdotes and have to be notched as interesting but not enough. Hector DeLuca, the giant in Vitamin D from Madison, who did the research on toxicity for the IOM stated on Public Radio that he could find no evidence of toxicity below 14,000 IU a day, and that toxicity was  a mild elevation in calcium.  

Most of the literature that I’ve read states that you get no evidence of toxicity until you get to about 40,000 IU a day.  That’s one mg. What the IOM is nervous about are the few case reports of associations between higher D levels and cancer.  That’s not toxicity per se, but the association is there.  Now, if we can use association studies to change our behavior, something the IOM strictly said they would not do and would only use randomized controlled trials, there are about 10,000 association studies showing beneficial effects of Vit D to the two or three that show some risk.  

The ones that catch my eye are the situations in which heart disease, Alzheimer’s, Parkinson’s, autoimmune, birth outcome, multiple sclerosis, diabetes, and many other rates of cancer drop dramatically with higher D levels.  There are many association studies showing that folks live longer when their D level is higher.   From lymphoma to melanoma, there are reports of folks living longer with higher D levels.  Melanoma, the archetype of sun exposure cancer, has a report in which patients with melanoma who cheated and went out in the sun against their doctors’ advice, lived longer than those who stayed indoors. 

 What’s a person to do?  I will step out and conjecture wildly.  I have to note that the majority of folks on the panel had something to do with bones.  They were all from academic centers where they were involved in research on osteoporosis.  Without any proof or evidence, I have to wonder who funds their research.   And if it's funded by companies who make osteoporosis drugs, would they be interested in losing their funding by advocating for Vit D instead of their expensive drugs.  

That’s a horrible allegation without any evidence.  It’s just a conjecture.  But it explains their discordant advice in a world confusing political forces and their unexplained caution.  “When you see something odd, follow the money and you will find the explanation.”  The rest of the wellness world has essentially written the IOM off as being strangely and excessively cautious.  I take a more sunny approach.  They doubled their prior cautious advice and raised the safe limit to 4000 IU.  Pretty good! 

 WWW What will work for me.  Heck, 4000 IU will get most folk's blood levels to about 50 ng.  That’s about what you would get to with 5 minutes of sunshine a day in shorts and a T-shirt.  So, unless we are forbidden to go out in the sun for 5 minutes, I’m not changing anything with the amount of D I’m taking.  I want to survive my heart attack, my stroke, delay my Alzheimer’s, and avoid my influenza…  I’ll take on the risk of slightly higher cancer for my pancreas and make up for it by eating more fiber.

(Editor's note:  From 2022, I've been taking 30,000 iu a day for several years now and sleep better. I did a genetic analysis on myself and found that I had some null deletions of Vitamin D receptors so I just need a much higher dose to get the stuff into my cells.  But as of 2022, I've still not seen toxicity, despite dozens of folks in my practice taking 30,000 IU-40,000 iu a day.  I've checked hundreds of calcium and D levels without any sign of cancer or elevated calcium.)

Column written by Dr John E Whitcomb, MD. Brookfield Longevity, Brookfield WI.