Treating autism spectrum disorder with gluten-free and casein-free diet: the underlying microbiota-gut-brain axis mechanisms

There is a rising interest in the use of dietary interventions to ameliorate prevalent brain diseases, including Autism Spectrum Disorder (ASD). Nowadays, the existence of communication between gut and brain is well accepted and thus diet can influence brain functioning. A well-known nutrition based intervention for ASD
is the gluten-free and casein-free diet. However, only some of the patients experience a relief in symptoms and thus efficacy seems to be limited to certain phenotypes. However, not much is known about the mechanism of action through which this diet might work, or about interpersonal differences that could lead to variation in response to the diet. Current evidence for efficacy of the GFCF diet is poor. Large scale, good quality randomized controlled trials are needed. Genetic and environmentally induced interpersonal differences were found in intestinal membrane permeability and blood brain barrier integrity as well as in activity of peptidase enzymes. These differences probably affect responsiveness to the diet. In addition, age and duration of the dietary intervention play a role in the efficacy of the gluten-free and casein-free diet. This is the reason why all these factors need to be taken into account to give appropriate advice about whether or not to
follow this diet.