How Much Vitamin D is Enough? - Not a Question for the Packers

August 23, 2010

How Much Vitamin D is Enough? 

 Reference: Time Magazine, August 20, 2010How much is enough?  

The American Institute of Medicine, in 1997, decreed that up to 2000 IU a day is safe, but that any more could be toxic.  With that warning, the whole world of organized medicine has been very cautious to go any higher.  Yet, we know from McMurdo Sound research that 2000 IU  a day to an audience that can’t get away, and doesn’t get any sun, results in a blood level of 29 ng.  Not enough. Time Magazine quoted three of the studies this column has reviewed in the past.  How 1100 IU of Vitamin D a day to women combined with a gram of calcium results in a 76% reduction in cancer within a couple of years.  It vaguely referenced that D will reduce risk for high blood pressure and diabetes.  It didn’t mention specifically the Intermountain Study released this spring that showed that D will reduce your mortality from heart attacks within a year or two, with additional benefit continuing up to a blood level of 46 ng.  Nor did they specifically mention that women taking D in South Carolina with Drs Hollis and Wagner demonstrated a marked reduction in risk for premature delivery, eclampsia and diabetes of pregnancy. 

 What’s changed and what Time Magazine didn’t get was that Vit D is really Hormone D.  Hormones affect your DNA and are the critical connection to maintaining your personal genetic code.  As important to your health and well being as thyroid, cortisol, estrogen, testosterone is a safe and healthy optimal level of D.  Hormones require a blood level to be at their optimum.  It’s time to start talking about what is your optimal blood level and how you achieve it. 

 My belief is as follows.  The data shows that you continue to get optimizing improvement in blood pressure until your Hormone D level is at 80 ng.  Humans exposed to sunlight year around with most of their skin will develop a blood level around 60-80 ng.  There has not been any toxicity demonstrated in folks with D below 150 ng (except in very rare illnesses in which high calciums happen naturally and dysfunctionally – and which you can treat by lowering the D level).   Our basement level then needs to be 46 ng, as that is what the largest recent research study shows is optimally beneficial.  Our target should be 60-80 ng. 

 How do you get there?  Easy.  If you are young (under 40), Caucasian (German, English, Polish, Danish, French), work outdoors every day, are skinny, wear few clothes, have no trouble with sun-burning, are not on any conflicting medications, you don’t need to take D during the summer and you can get away with 6 months a year of 4000 IU a day.  If you have skin pigment, work indoors, weigh a bit more than your wedding pictures, are older than 40, wear clothes, you need to take Hormone D year-round.  And the right dose is likely 4,000-8,000 IU a day.  On 4,000 IU a day, most people will be around 40-50 ng.  On 8,000 IU a day, most folks will be around 70 ng.  Heavy folks store a ton of D in fat tissue and need a much bigger loading dose to get to full.  Hence, in Wisconsin, we all need a lot!  We wear clothes, work indoors, are overweight, older than 40, have all sorts of lovely olive and brown and black skin colors.  Just get used to it. 

 WWW. What will work for me.  I’m taking 10,000 IU a day.  My level is 82 ng.  I avoid sun if I can because of my skin cancers.  My blood pressure went down 32 points in the last three years.  D was part of it.  Holly getting me out walking is part of it too.  Meet you at the park, wearing a hat.

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