Ameliorating Gastrointestinal Symptoms in Children With Autism Spectrum Disorder by Modulating the Gut Microbiota: A Systematic Review and Meta-Analysis.

This study looked at whether probiotics and similar treatments can help gut problems in autistic children. They found that 55% of autistic children have stomach issues. After reviewing 19 studies with over 1,000 children, researchers found these treatments did help reduce gut symptoms like constipation, diarrhea, and stomach pain. Treatments lasting 8 weeks or more worked better, and probiotics seemed especially helpful.

This systematic review and meta-analysis examined gut microbiota-modulating interventions (probiotics, prebiotics, synbiotics, and fecal microbiota transplantation) for gastrointestinal symptoms in children with autism spectrum disorder. Analysis of 19 trials (n=1154) found these interventions significantly improved gastrointestinal symptoms and reduced symptom severity scores by 1.86 points. Interventions lasting 8 weeks or longer showed greater effectiveness. The treatments increased beneficial Bifidobacterium bacteria levels and helped with constipation, diarrhea, abnormal stool consistency, flatulence, and abdominal pain.

Probiotics appeared particularly effective among the intervention types studied.

Gut microbiota-modulating interventions, particularly probiotics, can be considered as treatment options for gastrointestinal symptoms in children with ASD. Treatments should be implemented for at least 8 weeks for optimal effectiveness. These interventions may help manage constipation, diarrhea, abnormal stool consistency, flatulence, and abdominal pain commonly experienced by autistic children.

Studies lacked dietary control groups and dietary data collection. Small number of included studies (19) may have limited identification of sources of heterogeneity in pooled results. Sample sizes and methodological variations across studies not fully detailed.

Children with autism spectrum disorder (ASD) exhibit a high prevalence (55%) of gastrointestinal symptoms (GISs) and gut dysbiosis. Most studies involving children with ASD have focused on behavioral symptoms but not GISs. This systematic review and meta-analysis investigated the effects of gut microbiota-modulating interventions (GMMIs) on GISs and gut microbial composition in children with ASD. Five databases were searched for relevant domestic and international articles published from database inception until July 15, 2024.

The meta-analysis included human trials wherein children with ASD received prebiotics, probiotics, synbiotics, or fecal microbiota transplantation. Intervention effects were measured on the basis of α-diversity, and genus- and phylum-level data were analyzed using a random-effects model and forest plots. This study included 19 trials (n = 1154). The results indicated that GMMIs significantly ameliorated GISs (p = 0.0017), reduced six-item Gastrointestinal Symptom Index scores by 1.86 points (p = 0.0187), and significantly increased the relative abundance of Bifidobacterium spp. (p = 0.0205).

Longer interventions (≥ 8 weeks) were more effective in ameliorating GISs. Limitations in this investigation include the fact that the included studies neither incorporated any dietary control groups nor collected relevant dietary data, and the relatively small sample size (19 studies) may have hindered the identification of sources of heterogeneity in the pooled results. Overall, our findings suggest that GMMIs, especially probiotics, ameliorate GISs in children with ASD by modulating gut microbial composition, particularly by increasing the relative abundance of Bifidobacterium spp. These interventions may alleviate symptoms such as constipation, diarrhea, abnormal stool consistency and smell, flatulence, and abdominal pain.

Our evidence supports that treatments involving GMMIs can be considered for children with ASD.