Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: Based on parental report

Objectives: Studies on the gluten-free and/or casein-free (GFCF) dietary intervention for children with autism spectrum disorders (ASDs) suggest that some children may positively respond to implementation of the dietary intervention. Other research suggests that children diagnosed with ASD can be classified into subpopulations based on various factors, including gastrointestinal (GI) abnormalities and immune function. Methods: This study analyzes parental report data collected using a 90-item online questionnaire from 387 parents or primary caregivers of children diagnosed with ASD on the efficacy of the GFCF diet. Parents reported on their child's GI symptoms, food allergy diagnoses, and suspected food sensitivities, as well as the degree and length of their diet implementation. Results: Overall, diet efficacy among children whose parents reported the presence of GI symptoms, food allergy diagnoses, and suspected food sensitivities included greater improvement in ASD behaviors, physiological symptoms, and social behaviors compared with children whose parents reported none of these symptoms, diagnoses, or sensitivities (P < 0.05). Parental report of strict diet implementation, indicated by complete gluten/casein elimination and infrequent diet errors during and outside of parental care, also corresponded to improvement in ASD behaviors, physiological symptoms, and social behaviors (P < 0.05). Discussion: These findings suggest that various intricacies related to diet implementation and GI and immune factors may play a role in differentiating diet responders from diet non-responders and substantiate the importance of further investigations into the various, nuanced factors that influence efficacy of the intervention among children with ASDs.