Research synthesisLow evidenceModerate effect3 studies · 3 beneficial · 0 neutral · 0 harmful
Across 3 studies, all reported beneficial moderate-sized effects on reduced depression symptoms. Two of the three studies found statistically significant reductions. The evidence base includes a systematic review and a meta-analysis, but the studies primarily involve formulations containing *Lactobacillus plantarum* (a related species) rather than *Bifidobacterium plantarum* alone. Populations studied include adults with or without mood disturbances, patients with depression, and adolescents with depression; no consistent dose or duration was reported.
- Studied populations: adults with or without mood disturbances, patients with depression, adolescents with depression
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Evidence base is small (only 3 studies) — conclusions should be considered preliminary. The studies assessed *Lactobacillus plantarum* formulations rather than *Bifidobacterium plantarum*, and one study used multi-species products, so the specific effect of *Bifidobacterium plantarum* alone is unclear. Doses and durations were not consistently reported, limiting practical guidance.
Generated Jul 12, 2026