Antioxidant interventions in autism spectrum disorders: A meta-analysis

Background Autism spectrum disorder (ASD) might be associated with oxidative stress, and antioxidants are commonly used in the treatment of young people with ASD. However, the evidence about the effectiveness of these interventions remains debatable. We performed a meta-analysis to evaluate the effect of antioxidants on the symptoms of patients with autism. Methods: Data sources: PubMed and Web of Science databases. Study selection We selected placebo-controlled, double-blind, randomized clinical trials published until February 2021 to evaluate the efficacy of antioxidant interventions on ASD. Data analysis: Aberrant Behavior Checklist (ABC), Repetitive Behavior Scale-Revised (RBS), Social Responsiveness Scale (SRS), Developmental Behavior Checklist (DBC) and Clinical Global Impressions Severity scale (CGI-S) were used to evaluate the 22 different symptom outcomes. The Hedges-adjusted g value was used to estimate the effect of each dietary intervention relative to the placebo. Results: In this meta-analysis, we examined 13 double-blind randomized clinical trials, comprising a total of 570 patients with ASD: 293 in the intervention group and 277 in the placebo group. Antioxidants (N-acetylcysteine (NAC), other antioxidants) are more effective than placebos in improving the irritability among symptoms in the ABC and communication disturbance symptoms in the DBC. There was a good trend of improvement in the stereotypic behavior symptoms in the ABC. Treatment with NAC antioxidants showed a good trend of improvement in irritability in the ABC and symptoms of hyperactivity. The effect size was small, and there was a low risk of statistical heterogeneity and publication bias. Limitations The number of studies in this meta-analysis was small and the sample size was small. Conclusion This meta-analysis suggests that antioxidant intervention has a potential role in the management of some symptoms in patients with ASD, and indicates the feasibility of using antioxidants to treat autism in the future.