Dietary intervention for autism: a role for gluten and casein?

An extract, by Paul Whiteley of ESPA Research, from a new book,
Autism: exploring the benefits of a
gluten- and casein-free diet.
A practical guide for families and professionals
by Paul Whiteley, Mark Earnden &
Elouise Robinson

The use of a gluten- and casein-free (GFCF) diet for cases of autism continues to generate significant discussions in the lay and research communities. A new book aims to bring together the current collected research on the topic fusing research and practical information on how diet might affect some cases of autism.

Autism is a complex condition. Characterised by a dyad of core behavioural symptoms affecting social communicative functions accompanied by the presence of restricted or repetitive actions, significant heterogeneity occurs when it comes to the presentation of the condition. A diagnosis of autism or autism spectrum disorder (ASD) can also place a person at heightened risk of various other comorbid conditions potentially occurring. These range from learning disability to epilepsy to other more somatic issues such as sleeping problems and gastrointestinal (GI) problems being present alongside some cases of autism.

Although formally described in the 1940s (perhaps even earlier), relatively little is still known about autism: it’s aetiology and underlying processes causing and perpetuating presentation. What is becoming slightly clearer is that the presentation of core behaviours under the label of autism can likely occur as a result of several different factors converging. There is for example, a growing realisation that both genetics and environment may variably affect the risk of developing autism. That also autism or autistic-like behaviours occurs across several conditions or under different circumstances has led some to describe a more plural condition: the autisms.

In amongst the various investigations being carried out on the nature of autism and those examining how to improve quality of life for those on the autism spectrum, one seemingly odd area of research has evolved: a possible role for dietary intervention for some cases of autism. Based on work completed in the late 1970s / early 1980s, several research groups have examined whether use of specific dietary interventions removing gluten found in various cereal crops, and casein, the primary protein found in milk and mammalian dairy products, may impact on some of the presentation of autism for some people.

The results so far can best be described as interesting but with further research required. It is clear that a gluten- and casein-free (GFCF) diet is not a universal intervention for everyone with autism. Such a dietary change can also significantly affect day-to-day living for some in light of the quite stringent requirement for dietary adherence especially in the early days of intervention. To reiterate, this is not an intervention for everyone.

That being said, there is a growing realisation that in amongst the various ‘autisms’ there may be a subgroup of people who do positively respond to the use of GFCF diet, in terms of an amelioration of certain behaviours and increased use of daily living skills. Reports have similarly suggested positive changes to other symptoms outside of core autism, both behavioural and somatic for some adopting such a dietary change.

The precise reasons why the implementation of a GFCF diet might impact on the behavioural presentation of autism, some autism, remains a source of continued discussion. It is becoming clear that a diagnosis of autism does not seemingly afford any protection against the risk of developing other conditions; hence, case reports and some smaller group studies have reported on the presence of coeliac (celiac) disease as being comorbid to autism. Other groups have also reported on issues related to cow milk protein intolerance or lactose intolerance to be present in some people with autism. This implies that behavioural changes following adoption of a GFCF diet may reflect either some shared mechanisms involved in the genetics or biochemistry of such conditions, or that a reduction in discomfort or even pain following dietary intervention may partially explain any positive effect.

Other investigations have suggested other factors may be at work when it comes to the mechanism of effect from such a dietary change on cases of autism. Evidence is building for a role for the GI tract as being important, focused on either enzyme function (involved in metabolising the various products in gluten and/or casein) or gut barrier function (the so-called leaky gut). Issues with hyperpermeability of the intestinal barrier are of particular interest in light of the suggestion of immune system involvement in some autism. Although still the subject of significant speculation, some authors have also suggested further study of the gut microbiome - the collected trillions of bacteria which reside in the GI tract - to ascertain any involvement or not as a function of dietary intervention.

Despite the need for much greater research investment into the efficacy, long-term safety and mechanisms to explain the effects of a GFCF diet for some on the autism spectrum, this area remains a potential important one for autism research.

For further reading about the topic of gluten- and casein-free diets and autism and hints, tips and recipes for starting and following a GFCF diet, have a look at our book:
Autism: exploring the benefits of a gluten- and casein-free diet. A practical guide for families and professionals (Paul Whiteley, Mark Earnden & Elouise Robinson). Routledge. ISBN: 978-0-415-72763-1

The book is also available from Amazon.

First published May 2014

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