In a study on the efficacy of a gluten-free and dairy-free diet in autism, autistic symptoms and urinary peptide levels were monitored in subjects over 12 weeks. Only subjective improvement was noted by parents only in the symptoms of their children on this diet. (7)
A Cochrane Database Systematic Review evaluated several randomized clinical trials including diets free of gluten and/or casein, and noted that only small trial out of several reviewed reported a reduction of autistic traits, but a benefit in cognitive skills, linguistic ability and motor ability was not seen (8).
Food allergies and autism:
A study on the effects of food allergies and infantile autism shows that there is a possible relationship. According to a study in Italy entitled “Food allergy and infantile autism” done at the Department of Paediatrics, University of Rome Las Sapienza found that worsening neurological symptoms has been reported in autistic patients after consuming milk and wheat containing foods. In a study group of 36 autistic patients and 20 healthy controls, antibodies for milk proteins including casein, lactalbumin and beta-lactoglobulin were seen. After the elimination of these foods for an 8 week period, there was improvement in the behaviors of the autistic patients despite the fact that the milk antibodies were found to be higher in the controls. (9)