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 toameliorate prevalent brain diseases, including Autism SpectrumDisorder (ASD). Nowadays, the existence of communication betweengut and brain is well accepted and thus diet can influencebrain functioning. A well-known nutrition based intervention for ASDis the gluten-free and casein-free diet. However, only some of thepatients experience a relief in symptoms and thus efficacy seems tobe limited to certain phenotypes. However, not much is known aboutthe mechanism of action through which this diet might work, or aboutinterpersonal differences that could lead to variation in response tothe diet. Current evidence for efficacy of the GFCF diet is poor. Largescale, good quality randomized controlled trials are needed. Geneticand environmentally induced interpersonal differences were found inintestinal membrane permeability and blood brain barrier integrity aswell as in activity of peptidase enzymes. These differences probablyaffect responsiveness to the diet. In addition, age and duration of thedietary intervention play a role in the efficacy of the gluten-free andcasein-free diet. This is the reason why all these factors need to betaken into account to give appropriate advice about whether or not tofollow this diet