Insomnia is associated with differences in gut microbes
An observational review linked insomnia with lower gut microbial diversity and altered composition. It does not establish whether microbial changes cause sleep problems or follow them.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Across the included studies, insomnia was associated with lower gut microbial diversity and a different mix of bacteria. These patterns may help frame future research, but they do not establish a cause of insomnia. The abstract also does not demonstrate that changing gut microbes improves sleep or that microbial testing can reliably diagnose insomnia.
The reported observed-species estimate and confidence interval are internally inconsistent, so its size and direction cannot be interpreted reliably. The observational designs also leave the direction of the insomnia–microbiota relationship unresolved.
What researchers found
Gut microbiota composition
Adults with insomnia versus healthy controls across observational studies; assessment times were not reported. The abstract describes consistent differences without a single pooled effect estimate for this endpoint.
What differed between groups
Most studies reported lower diversity within individual gut samples in people with insomnia, while analyses comparing microbial communities found distinct patterns between groups. Some bacterial groups were less abundant and others more abundant.
Clinical applications remain untested
The review also described correlations with inflammatory markers and metabolic disturbances. In this abstract-based account, these remain biological associations; the proposed diagnostic and treatment applications were suggestions, without reported testing that established their clinical usefulness.
The original publication
The association between gut microbiota and insomnia: A systematic review and meta-analysis.
Chen S, Li H, Ning M et al.
Sleep Med Rev · 2026
- PubMed ID
- 41610732
- Record checked
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