Research synthesisModerate evidenceModerate effect3 studies · 3 beneficial · 0 neutral · 0 harmful
Across 3 studies, all reported beneficial moderate-sized effects on reducing depression symptoms, with 2 of 3 reaching statistical significance. The evidence primarily comes from reviews and meta-analyses including multi-species probiotics or Lactobacillus plantarum, with one review specifically targeting adolescents. No specific dose or duration could be identified due to inconsistent reporting.
- Studied populations: adults with or without mood disturbances; adolescents with depression
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. 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). Additionally, the studies often used multi-species formulations or Lactobacillus plantarum specifically, not Bifidobacterium plantarum; extrapolation to the single strain is uncertain. Lack of consistent dosing, duration, and form data further limits actionable conclusions.
Generated May 12, 2026