Probiotic supplementation and gut microbiota in children with autism: a pilot randomised controlled trial
A pilot RCT in 23 children with ASD found no significant changes in gut microbiota diversity following four months of multi-strain probiotic supplementation.
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What the study showed
Alpha- and beta-diversity did not differ significantly between probiotic and placebo groups. Bifidobacteriaceae increased significantly in the probiotic group (p = 0.046). Dominant phyla were Bacillota_A (~50%), Bacteroidota (~18%), and Actinobacteriota (~10%).
How it was done
Placebo-controlled randomised pilot trial in children aged 2–5 years with DSM-5-confirmed ASD; multi-strain probiotic (450 billion CFU) administered for four months; primary outcome was faecal microbiota diversity.
Risk of bias
Only 23 of the planned 40 participants were enrolled due to recruitment difficulties and COVID-19-related dropout, leaving the study statistically underpowered. Short-chain fatty acid and behavioural outcome data are not reported in the abstract.
What this study does NOT prove
No conclusion can be drawn that probiotics improve behavioural outcomes or overall microbiota diversity in children with ASD.
In clinical practice
Findings do not support a clinical recommendation for probiotics to modulate gut microbiota in children with ASD. The trial provides methodological guidance for future adequately powered studies.
Limitations
Only 23 of the planned 40 participants were enrolled due to recruitment difficulties and COVID-19-related dropout, leaving the study statistically underpowered. Short-chain fatty acid and behavioural outcome data are not reported in the abstract.
Technical appendix
Version history
- 1.0 · 2026-07-18 — Auto-generated under Evidence Standard v1.0
Paid access: structured summary from public metadata; consult the original study at the source.