Gluten- and casein-free diet and autism spectrum disorders in children: a systematic review

Anna Piwowarczyk, Andrea Horvath, Jan Łukasik, Ewa Pisula, Hania Szajewska

Effective treatments for core symptoms of autism spectrum disorders (ASD) are lacking. We systematically updated evidence on the effectiveness of a gluten-free and casein-free (GFCF) diet as a treatment for ASD in children. The Cochrane Library, MEDLINE, and EMBASE databases were searched up until August 2016, for randomized controlled trials (RCTs); additional references were obtained from reviewed articles. Six RCTs (214 participants) were included. With few exceptions, there were no statistically significant differences in autism spectrum disorder core symptoms between groups, as measured by standardized scales. One trial found that compared with the control group, in the GFCF diet group there were significant improvements in the scores for the 'communication' subdomain of the Autism Diagnostic Observation Schedule and for the 'social interaction' subdomain of the Gilliam Autism Rating Scale. Another trial found significant differences between groups in the post-intervention scores for the 'autistic traits', 'communication', and 'social contact' subdomains of a standardized Danish scheme. The remaining differences, if present, referred to parent-based assessment tools or other developmental/ASD-related features. No adverse events associated with a GFCF diet were reported. Overall, there is little evidence that a GFCF diet is beneficial for the symptoms of ASD in children.