Scientific American published a thought provoking article last month titled What If Vitamin D Deficiency Is A Cause Of Autism? This hypothesis was raised because of studies in Sweden and Minnesota that showed the rates of autism in Somali immigrants were three to four times higher than the general population. Vitamin D is known to absorb at much slower rates in darker skinned people than lighter skinned people and therefore in locations that receive very little sunshine it would make sense that darker skinned people would have a Vitamin D deficiency. However, the article never said whether this has been proven to be the case.
Still it should be a hypothesis that should and is being tested through large scale studies comparing Somali women and their children to the general population for combined instances of vitamin D deficiency and autism.
However, there are many things that could be causing this increase in autism in immigrant Somali populations that have nothing to do with Vitamin D.
1. Autism is not known in Somalia. Now this doesn’t mean it doesn’t occur, it is simply not diagnosed. This means potentially that amongst skilled immigrants especially in computer science and science migrating to Sweden and the US there could be quite a few of them with undiagnosed Aspergers or high functioning autism.
2. The Somali immigrant community is very insular. There are rarely any interracial marriages with the general populations in Sweden and Minnesota. Therefore, if you have these undiagnosed Aspies marrying each other, you are going to see a major increase in autism spectrum disorder in their offspring. This is exactly what we are currently seeing in Silicon Valley with its increase in autistic children which can not be contributed to a vitamin D deficiency.
I definitely see this new theory as food for thought but no one should be jumping to conclusions that a definitive cause of autism has been found. However, I bet we are going to be seeing the alternative medicine market marketing vitamin D to pregnant mothers as a way to prevent their kids from having autism.