Vitamin D- More Important Than Ever When We Lose Our Summer Sun

vitamin D and the sunshineWinter is fast upon us in the Northern Hemisphere, and if you live in the Pacific Northwest, you know we are in for many months without much sun.  There are only two ways to get enough Vitamin D:

  1. Adequate sun exposure (almost none of us get enough since we wear clothes, use sunscreen, and, for most of us, we work and play indoors much of the year).
  2. Take adequate Vitamin D as a supplement (Vitamin D fortified milk is not an adequate source).

Vitamin D is the one supplement you absolutely MUST take on an ongoing basis or suffer the severe consequences of deficiency, which involves bones and calcium absorption, as well as everything from neurological health and mood to cancer prevention and your immune system.

The British Journal of Nutrition has just published “A Systematic Review of Vitamin D status in Populations Worldwide,” (you can find it here… ) and found that the average person world wide has a Vitamin D level below 50 nmol/L. That is equivalent to less than 20 ng/ml (the units we are most familiar with).  Optimal Vitamin D status is thought to be 50-80 ng/ml. The article reviewed 195 individual studies involving 44 countries.  The levels were found to be the highest in North America.  Given that we know perhaps as little as 1% of those living in N. America have optimal levels, I think it is safe to say that the entire world is severely deficient in this key nutrient.

37.3% of the studies reviewed reported mean serum 25(OH)D values below 50 nmol/l, (<20 ng/ml) values considered inadequate by health authorities worldwide.

The NIH document on vitamin D (you can read it here… ) shows the following generally accepted conservative guidelines:


Serum 25-Hydroxyvitamin D [25(OH)D] Concentrations and Health
nmol/L** ng/mL* Health status
<30 <12 Associated with Vitamin D deficiency, leading to rickets in infants and children, and osteomalacia in adults
30–50 12–20 Generally considered inadequate for bone and overall health in healthy individuals
≥50 ≥20 Generally considered adequate for bone and overall health in healthy individuals
>125 >50 Emerging evidence links potential adverse effects to such high levels, particularly >150 nmol/L (>60 ng/mL)

* Serum concentrations of 25(OH)D are reported in both nanomoles per liter (nmol/L) and nanograms per milliliter (ng/mL).
** 1 nmol/L = 0.4 ng/mL

I recommend that teenagers and adults take 5000 IU daily of Vitamin D.  Newborns up to the weight of 40 pounds (20 Kg)  can take 1000 IU daily, and then increase the dose to 2000 IU daily for young children over 40 pounds.  Those children above 80 lbs (40 Kg) can take 3000 IU of Vitamin D3.  If you are afraid to take this amount of Vitamin D, then I propose you get your levels checked.

If you are taking more than these amounts or have been taking doses near what I am recommending, I also suggest you get your level checked to see if that is adequate.  There are huge health benefits by keeping your vitamin D level above 50 ng/ml (125 nmol/L).

I disagree with the NIH statement that > 20 ng/ml is “generally considered adequate for bone and overall health in healthy individuals”.  At that level you won’t remain a “healthy individual” for long!




Dr. Paul



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