Vitamin D and Flow Mediated Dilation: Link to Heart Disease

October 20, 2009

Replace Vitamin D and Make Your Blood Vessels Happy 

 Competency:  # 17 Vitamin D Reference:  Tarcin et at J Clin Endo Meta Oct 2009 p4023 

 Now, this is downright fun!  This is a well-done study comparing young, healthy men with low vitamin D levels (average 8 ng) to normal vitamin D levels (32ng) and what happens to their blood vessels as a result of Vit D replacement.  First of all, how did they replace it?  300,000 IU as a shot, once a month for three months.  That is the same as 10,000 IU a day for three months.  All with no side effects.  Nifty. Second, what they found when they raised the D blood level.  Blood pressure dropped by 7/7 points.  That’s huge by itself.  Then, they found that Flow Mediated Dilatation (how much your artery stretches and relaxes with a pulse is called FMD) improved to normal, which was a about a 30% increase.  That’s part of why the blood pressure dropped.  

They also found through multiple measures that “Oxidative Stress” decreased dramatically as they normalized the Vit D.  Finally, leptin was increased back to normal.  Leptin tells your brain that you are full.  With inadequate D, your leptin is low, and you eat too much because your brain doesn’t get the signal that you feel full and that you are deficient in leptin. This all points to a pattern of your arteries being prone to damage when your D is too low.  They don’t stretch as much, making your blood pressure higher.  Your arteries get more inflamed and your appetite is off kilter so you continue to provide too many calories by eating too much.   It’s all a perfect setting for damaged arteries.  It may not happen in just a month or two, but after twenty years you have a heart attack at age 42 and wonder how it happened.  

No one put the picture together for you and told you that this was yet another reason to take that irresistible Vitamin D. This study is a landmark study for a variety of reasons.  First of all, the authors were bold enough to use a replacement dose of D that focused on getting folks back to the same blood level as their control peers.  Their peers had an average level of 32 ng.  To get healthy young men with a blood level of 8 ng up to a blood level of 32 ng required 300,000 IU a month for three months.  That is almost a million units over 3 months.  This was done with no toxicity.  

This may help explain why prior studies in which D was given at 200 IU or 400 IU a day for a couple of months might not have shown much effect.  By focusing on the dose given instead of the blood level achieved, study subjects in many past negative D studies might never have gotten to therapeutic blood levels. In my opinion, 32 ng is still low as it is not what your body would naturally obtain by living in a sun-rich environment.  55 ng is my target. The pattern is falling together.  Many other studies show that Vit D is low in folks who have metabolic syndrome and that blood pressure will drop when adequate D is prescribed.  This study adds another reason to take D.  The summary is simple.  Low Vit D is as risky for you as any other risk factor for coronary artery disease. 

WWW.  What will work for me?  I’m taking vitamin D every day and my last level was 70.  Some folks think that may be a bit high.  I’m sticking with it.  The risks of coronary artery disease are real and very evident.  I have yet to find any risks with D supplementation that match it.   A kidney stone here and there can be awful, but nothing like sudden death from a heart attack.

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