Probiotics increased a blood biomarker, with very low certainty
A meta-analysis examined whether probiotics change blood levels of BDNF. The pooled increase does not establish an improvement in cognition, mental health or neurological disease.
Based on the published abstract. The full paper may contain additional methods, results and limitations.
The 30-second takeaway
Probiotic supplementation increased blood BDNF levels in the pooled analysis, but results differed markedly across trials and evidence certainty was very low. The review measured a biomarker rather than demonstrating a clinical benefit. Its analysis also did not find a statistically significant nonlinear relationship between probiotic dosage and BDNF levels.
The abstract does not supply the units for the pooled BDNF difference or describe control conditions. Very low evidence certainty and substantial variation between trials limit confidence in the result.
What was measured
The review focused on serum BDNF, a protein discussed in relation to brain plasticity and cognitive function. A change in its blood concentration does not, by itself, demonstrate improvement in those functions or in symptoms.
Duration and dose
Longer follow-up emerged as a source of differences between studies, and treatment duration had a nonlinear association with BDNF. These findings do not establish an optimal treatment length or show that a higher dose is better.
The original publication
Impact of probiotic supplementation on serum levels of brain-derived neurotrophic factor: GRADE-based dose-response meta-analysis.
Hashemi R, Raouf MMHM, Salih TS et al.
BMC Nutr · 2025
- PubMed ID
- 40790243
- Record checked
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