Efficacy and safety of probiotic supplements on cognitive function: a systematic review and meta-analysis of randomized clinical trials.
- 2025-11-25
- BMC complementary medicine and therapies 25(1)
- Nancy Calzada-Gonzales
- Ismael Moreno-Colina
- Linn Chu-Fuentes
- Daniel Andrade-Girón
- Hugo E Tito-Chura
- Carlos Quispe-Vicuña
- Pedro I Torres-Balarezo
- Anthony Bautista-Pariona
- Joshuan J Barboza
- PubMed: 41291638
- DOI: 10.1186/s12906-025-05149-6
Objective
This systematic review and meta-analysis aimed to evaluate the efficacy and safety of probiotic supplementation on cognitive function in individuals over 18 years of age.Methods
Randomized clinical trials (RCTs) assessing the impact of probiotics on cognitive function were included. Searches were conducted across four medical databases from inception to August 2024. The outcomes were cognitive function measured by Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Cognition Categorical Fluency Test (CFT), and adverse events. Data were extracted and analyzed using a random-effects model, with results reported as mean differences (MD) and relative risks (RR) with 95% confidence intervals (CI). To evaluate statistical heterogeneity, the I² statistic and the tau squared value (τ²) were used. The risk of bias was assessed using the RoB 2.0 tool, and the certainty of evidence was evaluated with GRADE.Results
A total of 34 RCTs involving 2,390 participants were included in the meta-analysis. Limited evidence suggests a possible improvement in cognitive function from probiotics use at 12 weeks (MD 4.23, 95% CI 2.77 to 5.68; certainty of evidence (CoE) was low, I² = 0%) for MMSE and cognitive function (MD 1.21; 95% CI 0.06 to 2.36; certainty of evidence (CoE) was low; I² = 35%) for MoCA; however, due to the very low certainty found, the evidence is very uncertain. On the other hand, probiotic supplementation can improve cognitive performance, as measured by CFT (MD 3.94, 95% CI: 3.20 to 4.69, low certainty of evidence; I² = 0%). Probiotics did not reduce the risk of any adverse event (RR 0.91, 95% CI 0.65 to 1.27; Certainty of evidence (CoE) was Very Low).Conclusions
Our study found that probiotics improved cognitive function, especially after 12 weeks of supplementation, using the MoCA test. However, although probiotics show potential benefits, the current evidence remains highly uncertain, warranting further rigorous trials.Research Insights
| Supplement | Health Outcome | Effect Type | Effect Size |
|---|---|---|---|
| Bifidobacterium plantarum | Improved Cognitive Function | Beneficial | Small |
| Bifidobacterium plantarum | No Change in Adverse Events | Neutral | Small |
| Lactobacillus plantarum HEAL9 | Improved Cognitive Function | Beneficial | Small |