Impact of probiotic supplementation on salivary function, oral microbiota, and gut health: a systematic review
Probiotics were associated with improvements in salivary parameters and reductions in cariogenic bacteria, but high heterogeneity limits conclusions.
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What the study showed
The review included six systematic reviews and found associations between probiotics and improved salivary buffering capacity, plaque pH, and reduced Streptococcus mutans. Beneficial effects on gut microbiota and gastrointestinal symptoms were also reported, suggesting an oral-gut microbiota interaction. Risk of bias ranged from low to high across included studies.
How it was done
Systematic review of randomized controlled trials involving human subjects, with searches in PubMed, Scopus, Web of Science, Science Direct, and Cochrane. Selection, data extraction, and risk of bias assessment (RoB 2.0) were conducted by two independent reviewers; meta-analysis was not performed due to heterogeneity.
Risk of bias
This is a review of systematic reviews, increasing the risk of redundancy and loss of granularity from primary data. Methodological heterogeneity precluded meta-analysis, and risk of bias varied widely among included studies.
What this study does NOT prove
The study does not prove causality between probiotics and caries prevention or measurable clinical improvement in gut health.
In clinical practice
There is insufficient basis from this study to recommend specific probiotic protocols for oral or gut health. Data should be interpreted cautiously given the reported methodological variability.
Limitations
This is a review of systematic reviews, increasing the risk of redundancy and loss of granularity from primary data. Methodological heterogeneity precluded meta-analysis, and risk of bias varied widely among included studies.
Technical appendix
Version history
- 1.0 · 2026-06-26 — Auto-generated under Evidence Standard v1.0
Paid access: structured summary from public metadata; consult the original study at the source.