Vitamin D Deficiency: Who Is Affected And At The Highest Risk?

sunshineVitamin D deficiency in my population of patients affects everyone! I have tested over 1000 children in the past 10 years and if you use the optimal levels of 50-80 ng/ml as the goal, only one or two were in that range and they were taking good doses of Vitamin D supplements.  Most were under 30 ng/ml and over half were in the single digits or teens, a state of severe deficiency.  OK, so I live and practice in Oregon, the Pacific NW corner of the USA where we have very little sun from November to June.  I have talked to colleagues in the southern states, and their experience is not much better.  It seems, even when we can get sun exposure, most of us spend the majority if not our entire day indoors, and when we do go out, we use sunscreen that blocks 99% of the Vitamin D production.

Dr Michael Holick’s book, “The Vitamin D Solution,” links this deficiency to conditions affecting 200 million (2/3) of the US population.  I tend to think that is about right.  If there was just one supplement everyone should take, it’s vitamin D.  Since vitamin D is actually a hormone with receptors in virtually all cells in our bodies, it affects heart issues, immune issues, inflammation, cancers, neurological conditions, obesity, and most of the diseases we think of as diseases of civilization.

There has been a 22% reduction in vitamin D levels in the past decade.

The darker your skin the less vitamin D you make as sun exposure to the skin is the only way our bodies can activate vitamin D.  The only other way to get Vitamin D3 is to take it as a supplement. This study shows that 70% of Whites,  90% of Hispanics, and 97% of Blacks in the US have insufficient Vitamin D levels.  I suspect near 100% have sub-optimal levels.  

Infants are particularly vulnerable as most of them start off very deficient due to mothers now being deficient.  Infants also get little or no sunlight exposure, and if breast feeding, there is no vitamin D fortification.  (I am not supporting formula feeding, just making a point that breast fed babies are especially in need of extra vitamin D).

The elderly tend to be outdoors less and thus become more and more vitamin D deficient.  Those who use sunscreen when outdoors, severely limit their vitamin D exposure (I am not supporting getting sun burned, but making a point that a little unprotected sun exposure, up to 15 minutes as long as it doesn’t cause a sunburn, is a good idea for your vitamin D production. Those who go outdoors with clothes covering most or almost all of their body will also not produce vitamin D.  The darker your skin the more melanin you have, which blocks the production of Vitamin D.  If you are darker skinned, you will want to take higher doses of Vitamin D3, or spend longer times in the sun without sunscreen. While there are some risks of too much sun exposure for non-melanoma skin cancers, these are miniscule in comparison to the multitude of health problems that come from low vitamin D levels.

Certain medical conditions put you at greater risk for vitamin D deficiency.  Those with fat mal-absorption, like cystic fibrosis or those with liver or kidney diseases or inflammatory bowel diseases, can have increased need for Vitamin D supplementation. 

In summary, it is likely that you and your loved ones need to take extra vitamin D.  While pregnant, take 3-5000 IU a day, newborns and infants should take 1-1,500 IU a day, children 2- 3000 IU a day, and teenagers and adults 3-5000 IU a day. If you have been taking a lot over more than a year faithfully, I recommend you get your level checked.  I suspect if you were taking less than 5000 IU a day, your levels will fine and you may find you need to take a little more to get into what I consider an optimal level of 50-80 ng/ml.  Levels above 100 ng/ml should be avoided and at 150 ng/ml you may begin to have toxicity symptoms.

Dr. Paul

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