Ameliorating Gastrointestinal Symptoms in Children With Autism Spectrum Disorder by Modulating the Gut Microbiota: A Systematic Review and Meta-Analysis.
Eight weeks of probiotic or synbiotic cuts GI distress in autistic children by restoring helpful gut bacteria.
01Research in Context
What this study did
Lu et al. (2025) pooled 19 randomized trials. The trials tested probiotics, prebiotics, synbiotics, or fecal transplants in children with autism.
All studies tracked tummy pain, constipation, diarrhea, and gut bacteria levels. The total sample was 1,154 children.
What they found
Kids who took probiotics or synbiotics for at least eight weeks had fewer GI symptoms. Their stools became more regular and painful cramps dropped.
The same children also grew more Bifidobacterium in their stools— a bacterium often low in autistic kids.
How this fits with other research
Andreo-Martínez et al. (2022) first showed autistic children usually lack Bifidobacterium. The new meta-analysis proves giving those bugs back eases pain.
Tan et al. (2021) said evidence was too weak to recommend probiotics. The 2025 data overturns that verdict— new trials now tip the scale.
Matson et al. (2009) tried oral immunoglobulin and saw no GI benefit. The contradiction is real: tweaking immunity failed, but tweaking microbes worked.
Why it matters
You can now safely suggest a probiotic or synbiotic to families struggling with constipation or diarrhea. Pick products with Bifidobacterium, run them for two months, and track stool logs. GI relief may also cut irritability that spills into teaching sessions, giving you clearer behavior data.
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02At a glance
03Original abstract
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.
Autism research : official journal of the International Society for Autism Research, 2025 · doi:10.1002/aur.70091