# Probiotic Depression Meta-analysis: What the Evidence Says
Canonical: https://www.migaku.app/guides/probiotic-depression-meta-analysis-evidence-review
Category: evidence-review
Summary: Probiotic Depression Meta-analysis has 2 source documents in the current Migaku evidence database. The strongest available sources in this first pass are syst
Last reviewed: 2026-06-02
Reviewed by: Migaku Evidence Review
# Probiotic Depression Meta-analysis: What the Evidence Says

## Quick Answer

Probiotic Depression Meta-analysis has 2 source documents in the current Migaku evidence database. The strongest available sources in this first pass are systematic review, so conclusions should be framed as evidence-aware guidance rather than medical advice.

## Key Takeaways

- This page is generated only from sources stored in the Migaku evidence knowledge base.
- Current evidence mix: 2 systematic review.
- Claims should be interpreted with the source type, study design, population, and publication date in mind.
- This article is educational and does not replace care from a qualified clinician.

## Evidence Map

| Source | Evidence type | Level | Date | Identifier |
| --- | --- | ---: | --- | --- |
| The effect of probiotic and synbiotic supplementation on sleep parameters in exercised population: a systematic review and synthesis without meta-analysis (SWiM) of randomized controlled trials | systematic review | 1 | 2026-05-25 | 10.1080/15502783.2026.2670564 |
| Efficacy of probiotic intervention in unmedicated depression: a systematic review and meta-analysis | systematic review | 1 | 2026-01-07 | 10.3389/fpsyt.2025.1608238 |

## What The Sources Report

- A 2024 meta-analysis of randomised, placebo-controlled trials found that probiotics reduced Pittsburgh Sleep Quality Index (PSQI) scores at 4-6 and 8-16 weeks and delivered small but significant gains in sleep efficiency; effects on sleep duration and insomnia severity were less consistent, and risk-of-bias/potential publication bias were noted. [Salehi Asl Mina (2026); evidence level 1]
- 14 18 Evidence specific to exercise populations remains limited and heterogeneous. [Salehi Asl Mina (2026); evidence level 1]
- Individuals with depression exhibit distinct gut microbiota profiles, including reduced abundance of short-chain fatty acid (SCFA)-producing bacteria (e.g., Faecalibacterium and Roseburia) and elevated pro-inflammatory cytokines (e.g., IL-6, TNF-α), correlating with depression severity. [Haiyan Liu (2026); evidence level 1]
- This analysis addresses key limitations in existing evidence by focusing specifically on studies of probiotic monotherapy in unmedicated individuals, a design that minimizes confounding by psychotropic drugs. [Haiyan Liu (2026); evidence level 1]

## How To Read This Evidence

Evidence level 1 generally reflects systematic reviews or meta-analyses. Level 2 includes randomized trials, guidelines, or public-health guidance. Level 3 usually reflects observational or narrative-review evidence. Level 4 is weaker or early-stage evidence. The level is a sorting aid, not a final quality grade.

## Practical Interpretation

There is at least one systematic-review style source in the current set, so it deserves more weight than single-study evidence. For probiotic depression meta-analysis, the next editorial step is to add more targeted sources and separate strong findings from early or indirect evidence.

## Limits Of This First Pass

This is a small-batch MVP article. It uses the first ingested sources for this topic and should be expanded with more targeted searches, license review, and human editorial checks before being treated as a definitive review.

## References

- Salehi Asl Mina (2026). The effect of probiotic and synbiotic supplementation on sleep parameters in exercised population: a systematic review and synthesis without meta-analysis (SWiM) of randomized controlled trials. DOI: 10.1080/15502783.2026.2670564. PMCID: PMC13202683. PMID: 42184272. License: CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC13202683/
- Haiyan Liu (2026). Efficacy of probiotic intervention in unmedicated depression: a systematic review and meta-analysis. DOI: 10.3389/fpsyt.2025.1608238. PMCID: PMC12819584. PMID: 41573044. License: CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC12819584/

## Safety Note

Health information can change, and individual risk depends on medical history, medications, pregnancy status, age, and diagnosis. Talk with a qualified clinician before changing treatment, supplement, or medication routines.