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Study: Gluten/casein-free diet doesn’t improve autism symptoms

Small, carefully controlled study finds gluten/casein-free diets don’t improve behavior or bowel symptoms in kids with autism; larger studies needed
September 15, 2015


UPDATE: See our Q&A with senior study author Susan Hyman.

A small, carefully controlled study found no improvement in behavior, autism symptoms, sleep patterns or bowel habits when children with autism were placed on a gluten-free, casein-free diet. But the researchers caution that larger studies are needed to determine whether there are small subgroups of children who would benefit. 

The diet is popular among families who have children with autism. Some propose that gluten (a protein found in wheat and some other grains) and casein (a protein found in dairy products) can worsen autism symptoms by causing inflammation in the gut that spreads to the brain.

The study findings appear online in the Journal of Autism and Developmental Disorders.

In the study, the researchers first placed 14 children with autism, ages 3 to 5 years, on a gluten/casein-free diet for 4 to 6 weeks. Then, over the following 12 weeks, they sent home look-alike, taste-alike snacks and meals that either contained gluten and/or casein or were gluten/casein-free. Neither researchers nor parents knew when a child was getting food containing gluten and/or casein until the end of the study.

Meanwhile, parents completed detailed questionnaires on their children’s behaviors, sleep patterns and bowel movements. (Many children with autism suffer from chronic constipation and/or diarrhea.) 

When the researchers broke the code to see when each child received gluten and/or casein foods, they found no pattern of improvement or worsening of behavior or other issues.  

At the same time, the researchers found that – with nutritional counseling – families can adopt a gluten/casein-free diet without causing nutritional deficiencies in their children.

They call for larger studies enrolling more children to see if there is a small subset of children whose autism symptoms are helped by the diet. Such studies need to ensure that neither parents nor researchers know when children are eating gluten and/or casein, they say, so that expectations don’t influence results.

The research was led by Susan Hyman, who co-leads the Autism Speaks Autism Treatment Network site at the University of Rochester Medical Center. It was supported by research grants from the National Institutes of Health and the University of Rochester.

For more on the study, also see “Autism Isn’t Helped by Gluten-Free Diet: Study,” in the Wall Street Journal.

Also see “How helpful is the casein-gluten-free diet?” in the Autism Speaks Food for Thought blog.