Food and Behaviour Research

Donate Log In

Vitamin D the clue to more Autism spectrum disorder in boys

University of Queensland

more FAB news

A deficiency in Vitamin D on the mother's side could explain why Autism spectrum disorder is three times more common in boys, say researchers from The University of Queensland.

FAB RESEARCH COMMENT:

Vitamin D is of course critical for a healthy immune system (as well as strong bones and teeth) - but far less attention is paid to its crucial importance for healthy brain development and function.

For decades, research has been building up showing that Vitamin D deficiency in pregnant mothers increases the risks in their children for difficulties with mood, behaviour and learning - including autism, ADHD and other neurodevelopmental or psychiatric disorders.

Now, a new study of the effects of Vitamin D deficiency in pregnancy has provided an explanation for why autism and related conditions are more common in males: A lack of Vitamin D in the mother increases the unborn baby's exposure to testosterone - which is known to affect brain development in ways that raise risks for autism, ADHD and related conditions. 

For the related research article please see:

For further information on vitamin D please see:
11/12/2020 - EurekAlert

A deficiency in Vitamin D on the mother's side could explain why Autism spectrum disorder is three times more common in boys, say researchers from
The University of Queensland.

In their latest study, Professor Darryl Eyles and Dr Asad Ali from UQ's Queensland Brain Institute found vitamin D deficiency during pregnancy caused an increase in testosterone in the developing brain of male rats.

"The biological cause of Autism spectrum disorder (ASD) is unknown but we have shown that one of the many risk factors--low vitamin D in mothers--causes an increase in testosterone in the brain of the male foetuses, as well as the maternal blood and amniotic fluid," Professor Eyles said.

"In addition to its role in calcium absorption, vitamin D is crucial to many developmental processes.
"Our research also showed that in vitamin D-deficient male foetuses, an enzyme which breaks down testosterone was silenced and could be contributing to the presence of high testosterone levels."

Professor Eyles' previous research has shown that vitamin D plays a critical role in brain development and that that giving vitamin D supplements to mice during pregnancy completely prevented ASD-like traits in their offspring.

Co-author Dr Ali said that excessive exposure of the developing brain to sex hormones like testosterone was thought to be an underlying cause of ASD, but the reasons remained unclear.

"Vitamin D is involved in pathways controlling many sex hormones," Dr Ali said.

"When the rat mothers were fed a low vitamin D diet, it caused male foetal brains to have high levels of exposure to testosterone."
Professor Eyles said the study was the first to show that a known risk factor for ASD alters testosterone in both the foetal brain and the mother's blood -- one possible contributor to why ASD is more prevalent in males.

"We have only studied one risk factor for ASD -- vitamin D deficiency during development -- our next step is to look at other possible risk factors, such as maternal stress and hypoxia - lack of oxygen - and see if they have the same effect," he said.