Probiotics have not shown a clear cognitive benefit in older adults
A review of trials in older adults found no statistically clear improvement in cognitive test performance with probiotics. Substantial differences between studies limited the combined result.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
The pooled trials did not establish that probiotic supplementation improved cognitive performance in older adults. The estimated result leaned toward improvement, but its uncertainty included no difference and effects in the opposite direction. The trials also differed substantially, so the abstract cannot identify a reliable overall benefit or a particular probiotic regimen with demonstrated effectiveness.
The abstract omits supplement details, control conditions, and treatment lengths. The authors report enough variation between trials to prevent determining a reliable overall effect size.
What researchers found
Combined cognitive test performance
The pooled standardized score difference was not statistically significant. Trial comparators and assessment timeframes are not specified in the abstract.
What cognitive performance meant
Researchers combined results from cognitive tests, using a standardized measure to put different scores on a common statistical scale. That measure describes test performance; it is not a percentage improvement or a demonstrated change in everyday functioning.
Inflammation was a separate outcome
Some trials also measured inflammatory signals in blood. Their combined result did not show a statistically clear reduction. These laboratory measurements are distinct from cognitive tests and do not establish that changes in inflammation explain cognitive outcomes.
The original publication
The role of probiotics in the improvement of cognitive performance of older adults: a meta-analysis.
Wiegers C, Doğan S, Metzelaar M et al.
Benef Microbes · 2025
- PubMed ID
- 40483001
- Record checked
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