Effects of gut microbial-based treatments on gut microbiota, behavioral symptoms, and gastrointestinal symptoms in children with autism spectrum disorder: A systematic review

Many studies have identified some abnormalities in gastrointestinal (GI) physiology (e.g., increased intestinal permeability, overall microbiota alterations, and gut infection) in children with autism spectrum disorder (ASD). Furthermore, changes in the intestinal flora may be related to GI and ASD symptom severity. Thus, we decided to systematically review the effects of gut microbial-based interventions on gut microbiota, behavioral symptoms, and GI symptoms in children with ASD. We reviewed current evidence from the Cochrane Library, EBSCO PsycARTICLES, PubMed, Web of Science, and Scope databases up to July 12, 2020. Experimental studies that used gut microbial-based treatments among children with ASD were included. Independent data extraction and quality assessment of studies were conducted according to the PRISMA statement. Finally, we identified 16 articles and found that some interventions (i.e., prebiotic, probiotic, vitamin A supplementation, antibiotics, and fecal microbiota transplantation) could alter the gut microbiota and improve behavioral symptoms and GI symptoms among ASD patients. Our findings highlight that the gut microbiota could be a novel target for ASD patients in the future. However, we only provided suggestive but not conclusive evidence regarding the efficacy of interventions on GI and behavioral symptoms among ASD patients. Additional rigorous trials are needed to evaluate the effects of gut microbial-based treatments and explore potential mechanisms.