Vitamin D & Latitude - It Could All Be Wrong
The Institute of Medicine (IOM) recently published it’s latest Vitamin D and Calcium recommendations. The IOM says that most people are not deficient in these nutrients and that supplementation is unnecessary for most.
This fits my “Humans Are Not Broken, by Default” stance, but so what, right? There are several people and organizations who disagree with the findings (Vitamin D Council, Dr. William Davis, Richard Nikoley, and others).
I’m a big fan of Chris Masterjohn’s work. He writes at:
- The Weston A. Price web site: http://www.westonaprice.org/blogs/blogger/CMASTERJO/
- Cholesterol-and-Health: http://www.cholesterol-and-health.com/
- The Daily Lipid: http://blog.cholesterol-and-health.com/
Masterjohn has been cautious, and is one of the few I am aware of who is actually looking at the full 999-page IOM report. He has said that he will be reporting back on that soon.
In his latest article, Chris points us to research indicating that everything we know about Vitamin D and latitude may be wrong. It turns out that what we do know is based on:
The 1988 data, to which Michael Holick contributed, has been the most important data set used for understanding the vitamin D winter. They measured vitamin D production in a handful of cities using isolated pieces of skin or 7-dehydrocholesterol mixed into a test tube concoction.
Imagine that. You mean “isolated pieces of skin or 7-dehydrocholesterol mixed into a test tube concoction” might not be a perfect model for real-live human sunlight absorption and Vitamin D synthesis? Seriously!? I’m guessing most of us didn’t know we were relying on this to form the basis of our present knowledge.
A major analysis published in 2009 (3) pooled together the results of 394 studies examining vitamin D levels in over 30,000 people all across the globe in order to investigate the effect of latitude on vitamin D status. The authors only included people who were native to the area in which they were living, and who were free-living. They concluded that there was only an effect of latitude in Caucasians. There was no effect of latitude in people with non-Caucasian ancestry.
The reason this deals such a major blow to the latitude hypothesis is that it is precisely people with white skin who dwell outside the equatorial regions who are supposed to be among the most vulnerable, but Caucasians actually had 45% higher levels of vitamin D than non-Caucasians!
If, in fact, the “original” humans best adapted to their environments are those who never came “out of Africa,” we must wonder why they have, on average, lower vitamin D status than Caucasians living in more northerly regions.
You can read Chris Masterjohn’s full article here: http://www.westonaprice.org/blogs/2010/12/24/vitamin-d-problems-with-the-latitude-hypothesis/
For now, I am very comfortable not supplementing, eating a natural Paleo diet, exercising, getting plenty of sunlight without sunscreen. I’m banking on two things: 1) Healthy humans are not broken, by default and 2) having evolved for millions of years without Vitamin D supplements — it needs to be proven further that D-supplementation is beneficial to the overall health of healthy human beings (not the other way…that everyone ought to take Vitamin D pills until it’s proven that they aren’t beneficial).