Food and Behaviour Research

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Autism and vitamin D

Cannell JJ (2008) Medical Hypotheses 70(4):750-9.  Epub 2007 Oct 24. 

Web URL: View this and related abstracts via PubMed here


Any theory of autism’s etiology must take into account its strong genetic basis while explaining its striking epidemiology.

The apparent increase in the prevalence of autism over the last 20 years corresponds with increasing medical advice to avoid the sun, advice that has probably lowered vitamin D levels and would theoretically greatly lower activated vitamin D (calcitriol) levels in developing brains.

Animal data has repeatedly shown that severe vitamin D deficiency during gestation dysregulates dozens of proteins involved in brain development and leads to rat pups with increased brain size and enlarged ventricles, abnormalities similar to those found in autistic children.

Children with the Williams Syndrome, who can have greatly elevated calcitriol levels in early infancy, usually have phenotypes that are the opposite of autism. Children with vitamin D deficient rickets have several autistic markers that apparently disappear with high-dose vitamin D treatment.

Estrogen and testosterone have very different effects on calcitriol’s metabolism, differences that may explain the striking male/female sex ratios in autism. Calcitriol down-regulates production of inflammatory cytokines in the brain, cytokines that have been associated with autism.

Consumption of vitamin D containing fish during pregnancy reduces autistic symptoms in offspring. Autism is more common in areas of impaired UVB penetration such as poleward latitudes, urban areas, areas with high air pollution, and areas of high precipitation.

Autism is more common in dark-skinned persons and severe maternal vitamin D deficiency is exceptionally common the dark-skinned.

Conclusion: simple Gaussian distributions of the enzyme that activates neural calcitriol combined with widespread gestational and/or early childhood vitamin D deficiency may explain both the genetics and epidemiology of autism. If so, much of the disease is iatrogenic, brought on by medical advice to avoid the sun. Several types of studies could easily test the theory.


For some years FAB Research has been drawing attention to

(1) the mounting evidence that Vitamin D deficiency in mothers during pregnancy may affect brain development in the resulting children, potentially raising the risks for neurodevelopmental disorders like ADHD, autism, dyspraxia and schizophrenia, and

(2) the high apparent prevalence of very low Vitamin D status (deficiency or insufficiency) in both the general population of the UK and in many other countries 

In this article, John Cannell MD (founder of the not-for-profit Vitamin D Council), reviews this and other evidence to argue that Vitamin D deficiency could potentially play a key role in explaining the apparent increase in rates of autism in recent years.

As he also emphasises, this hypothesis is eminently testable - and if correct, could offer new, low-cost options for the prevention and possibly even the management of autism and related conditions.

See also:

Harms et al 2008 - Developmental vitamin D deficiency alters adult behaviour in mice.

16 July 2007 - The Telegraph - Why Vitamin D Is So Vital

26 June 2006 - BBC News - Rickets rises among city's young

Lucas et al 2006 - Is the current public health message on UV exposure correct?

Becker et al 2005 - Transient prenatal vitamin D deficiency is associated with subtle alterations in learning and memory functions in adult rats.

Feron et al 2005 - Developmental Vitamin D3 deficiency alters the adult rat brain.

Kalueff et al 2004 - Increased anxiety in mice lacking vitamin D receptor gene

Kalueff et al 2004 - Impaired motor performance in mice lacking neurosteroid vitamin D receptors

Mackay-Sim et al 2004 - Schizophrenia, vitamin D, and brain development.

Burne et al 2004 - Transient prenatal Vitamin D deficiency is associated with hyperlocomotion in adult rats.

Eyles et al 2003 - Vitamin D3 and brain development.