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What are “normal” human vitamin D levels?

I assume the lifeguards were caucasian? With a “built in” SPF of 15 what blood level of Vit D does the lifeguard of African descent attain? Perhaps that is a better clue for evolutionary “normal”.

CapeBreton / Originally Posted in Evolutionary argument for optimal vitamin D level

Answer:

You’re absolutely right, CapeBreton. Considering the average vitamin D levels of clothed high latitude office workers “normal” for our species doesn’t make much sense and though lifeguards are at least outside all day and half naked, they were still both Caucasian and Missourian. A more representative normal level of the “sunshine vitamin” could be gleaned measuring levels in those with black skin who live scantily clad in equatorial Africa. The problem is that such a study has never been done–until now.

This month researchers published results from the Maasai and the Hadzaben and the title says it all: “Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l.” So lower than the pale St. Louisans, but still nearly twice the levels found in most Americans. No change to my recommendations, though, summarized in the culmination of my two week vitamin D series: Resolving the vitamin D-bate.

Image credit: Steve Slater (Wildlife Encounters) / Flickr

Dr. Michael Greger

About Michael Greger M.D.

Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

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