A Tale of Two D’s The Devil is in the “D”tails

December 05, 2010

A Tale of Two D’s:  The Devil is in the “D”tails 

 Reference2010  Vitamin D Guidelines from the Institute of Medicine Dec 2, 2010 

 The new guidelines for Vitamin D from the Institute of Medicine have just been issued.  Taken objectively, they triple the level of Vit D that adults should take to 600 IU a day from the prior 200 IU.  They also double the upper limit of “safety” to 4,000 IU a day.  But that’s not the story that got played in the media.  The media talked all about the limits of safety and the risk of cancer at higher doses.  

What’s the truth? This may take a few more emails to completely sort out, but I wanted you to know something today.  Personally, I’m changing nothing.  I think they missed a huge opportunity to make a meaningful change.  

Here are the errors that I see in their logic.   First, they are using Randomized Controlled Trials as their sole source of truth. That method serves us well in short-term diseases.  The problem with RCTs in long-latency disease is that you can’t get someone to do an intervention in a double-blind fashion for years when you feel no effect.  

The Women’s Health Study, giving only 200 IU a day, had very dramatic drop-offs in compliance.   And it showed very little effect.  No wonder.  200 IUs is what your body makes in 12 seconds of good sunshine.  They didn’t use the epidemiological evidence that begs for interpretation and weaves a web of logical inferences.  They still are inferences. They still haven’t been proven by a focused trial.  

But that’s another fallacy they didn’t address. Vit D is not a vitamin.  It is a hormone that affects 10% of the human genome.  Its effect is to have a broad improvement in physiology that you can’t ferret out with a study on just one single system. It did mention the risk of cancer.  Here there may be some concern to address. But I’m not sure how much.  We’ve known for almost 100 years that farmers in Minnesota have lower cancer rates than office workers.  Is that a beneficial D effect?  We also know there is a 30-40% gradient from north to south USA on about 9 different cancers.  We also know the African American community gets more cancer in the north than the white community.  We also know that melanoma patients who defy their doctors and go back out in the sun live longer than those who stay indoors.  And about 10 other cancers show the same effect.  

You live longer with a high D level.  But more recently, the Uppsalla longitudinal study of men in Sweden showed a slight uptick in cancer rates at higher D levels.  But that begs the question, how high and how much risk, and is that repeatable compared to all the others? It just defies reason and logic to say that a Vit D level of what humans naturally make in sunshine is dangerous.  The IOM did not address the variability from north to south.  It did not talk about D as a hormone.  It did not address the huge opportunity of D around pregnancy, mental health.  It stated it could measure no effect on D on autoimmune disease.  What do I do when I have personally seen people with psoriasis tell me they were completely cured with Vit D at 5,000 IU a day?    That’s just 5 minutes of sunshine.  I don’t get sick with 5 minutes of sun. 

 WWW.  What Will Work for Me.  I’m puzzled and I’m going to sit tight for right now.  I think we need to look at the same data the IOM looked at, and parse it out some more.  But the real story is that we now have a doubling of our upper safe limit.  4000 IU a day will get most folks to a blood level of 50-60, which is what your body makes in good sunshine.  Maybe we should just look at the positive side.  And maybe we should really focus on all of us getting it for the next 5 months of winter when in Wisconsin we get none.  And that includes our kids.  1000 IU a day for them too!

The column written by Dr. John E Whitcomb, MD, Brookfield Longevity, Brookfield, WI.   262-784-5300