June 21, 2010
Vitamin D Deficiency Due To Genetic Variants

If you are low in vitamin D it might be due to your genes.

An international research consortium has identified four common gene variants that are associated with blood levels of vitamin D and with an increased risk of vitamin D deficiency. The report from the SUNLIGHT consortium involving investigators from six countries will appear in The Lancet and is receiving early online release.

"We identified four common variants that contributed to the risk for vitamin D deficiency," says Thomas Wang, MD, of the Massachusetts General Hospital (MGH) Heart Center, a co-corresponding author of the Lancet report. "Individuals inheriting several of these risk-associated variants had more than twice the risk of vitamin D deficiency as was seen in those without these variants."

So the obvious question: What selective pressure produced genetic variants that lower blood vitamin D level? What was (and perhaps still is) the selective benefit of absorbing less vitamin D, breaking it down more rapidly, or synthesizing less of it in the skin? Did people who work outside (i.e. most humans for most of human history) produce too much vitamin D?

Four common genetic variants contribute to higher risk of vitamin D deficiency.

The SUNLIGHT (Study of Underlying Genetic Determinants of Vitamin D and Highly Related Traits) Consortium involved a research team from the U.S., U.K., Canada, Netherlands, Sweden and Finland who pooled data from 15 epidemiologic studies of almost 32,000 white individuals of European descent. Results of the comprehensive genetic screening were correlated with participants' serum vitamin D levels. Statistically significant associations were found for four common variants, all in genes coding enzymes involved with the synthesis, breakdown or transport of vitamin D. The risk association was independent of geographic or other environmental factors; and the more variants an individual inherited, the greater the risk of vitamin D deficiency.

Should the recommended daily allowance of vitamin D be based results of genetic tests? Seems like that makes sense.

The big studies done on how diet, lifestyle and other factors influence disease risks should all include collection of genetic samples so that as genetic testing becomes cheaper the DNA of all study participants can be sequenced. An obvious question from this study: Do some of the genetic variants that lower blood vitamin D also increase risk of osteoporosis, cancer, heart disease, or other diseases? Or maybe do any of these genetic variants lower disease risks?

Share |      Randall Parker, 2010 June 21 10:36 PM  Nutrition Genomics


Comments
James Bowery said at June 22, 2010 11:21 AM:

Such DNA tests will tend to validate the specious social construct of "race" with the attendant horrors such as The Holocaust. DNA tests should be permitted only by special license from the EEOC to ensure it isn't being abused for racist purposes.

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