Vitamin D and Hypertension Risk

July 08, 2013

Vitamin D and Hypertension Risk 

 ReferenceEuropean Genetics Conference in Paris, Jun 2013 

 It’s summer, the sun is out, we are all outside playing in the beautiful sunshine.  And getting our Vitamin D.  That means we are lowering our blood pressure.  At least according to Dr. Karani S, the lead researcher in the University College, London study.  Because there have been many inconsistent findings about Vitamin D and cardiovascular risk, the research team decided to pool every study they could find that was of sufficient quality and bring a whole new methodology of study to settle the issue of causality. This is a powerful new tool in genetics.  

Taking genetic variability in human and measuring “SNPs”, or “Snips”, (single nucleotide polymorphisms) they tested for a causal relationship between Vitamin D status and hypertension.  The tool they called Medelian randomization allows cause and effect conclusions to be identified despite the many confounding background problems like actual blood levels, skin type, time of year, level of blood pressure and all the other variabilities that make for a such complexity that clear conclusions get lost.  As we get better at studying SNPs and our genes, more research of this type might be forthcoming.  “Mendelian Randomization”. 

This study took 35 studies with 155,000 participants in them.  That makes it pretty credible because of its size.   The conclusion was clear.  For every 10% increase in Vitamin D blood level, there was an 8.1% decrease in risk of developing hypertension. How does this translate into everyday life?  In Wisconsin, most of us have Vitamin D levels that are higher in the summer than in the winter.  We vary from levels of about 40 ng in the summer with Caucasian folks who have skin that tans but can burn (Skin Type III) and who get outside and garden, play golf, bike and hang out at the pool to 12 ng for folks with Skin Type V (most African Americans).  Asians, middle Eastern folks and Hispanics with variable skin pigment levels have variable sun absorption qualities somewhere in-between.   

In the winter, we drop down to 15 ng for Caucasians, and 6 for African Americans. My level was 7 ng when I first measured my Vitamin D level some 10 years ago.  My blood pressure was in the 130s.  My blood pressure today is usually in the 115s.   I am a knowledge worker who is usually indoors and my dermatologist makes sure I’m covered up to protect me from any more skin cancer.  When I garden, it’s usually in the late afternoon or evening, or early morning.   I’ve seen Vitamin D drop many peoples’ blood pressure in the range of 5-10 points.   I believe this research. 

WWW.  What will work for me.  I’m getting older so my skin doesn’t make the D it used to.  So I take my supplement every day.  I want a blood level somewhere in the 50-60 ng range which requires me to be on about 5,000 IU a day.  We know that is the equivalent of about 5 minutes of sunshine. (At age 20, skin type III makes 1000 IU of D a minute)  Be wary of those who tell you that anything over 800 IU a day may be toxic.  They are telling you, usually with great sincerity and a very straight face that more than 10 seconds of sunshine might be toxic.  (Be sure to run from your car to your house so you don’t get toxic blood levels! Tongue in cheek.)  If you have skin pigment of a variable degree, please, please, please don’t stop at 800 IU a day. You MUST be on more D.  If you are African American in Wisconsin, this could explain part of the runaway epidemic of hypertension in the AA community.   

 Pop Quiz 

 1.  If you have more Vitamin D in your blood, your risk of developing high blood pressure drops.  T or F                        Answer:  True. You got the gist of it. 

 2.  Caucasians with light skin absorb more sunlight and make Vitamin D faster than folks with skin pigment.  T or F                    Answer. True. 

 3.   African Americans in Milwaukee have more hypertension than Caucasians.  T or F              Answer:  True.  This is clearly not sufficient to make it a pure causal connection but it sure could be part of the picture. 

 4.  For every 10% increase in Vitamin D, the risk of hypertension goes down 8%.  T or F               Answer:   True. 

 5.   The Institute of Medicine recommends 800 IU a day for bone health.  Many health care systems in Milwaukee warn against higher levels.  They are being too timid to your detriment.  T or F                       Answer:   True 

 6.  Innovation in health care takes 17 years to get from research to the bedside.  Your health care system may be slow.  Do you want to wait?                         Answer:  No.  Take the D

This column was written by Dr. John Whitcomb, Brookfield Longevity, Brookfield, WI.