Evaluation of the clinical efficacy of <i>Pediococcus acidilactici</i> CCFM6432 in alleviating depression

Aim: Accumulating evidence highlights the crucial role of the “gut-brain axis” and emphasizes the potential of dietary interventions to improve brain health through this pathway. This study assesses the effects of the probiotic Pediococcus acidilactici CCFM6432 on mood, sleep, and gastrointestinal function in patients with depressive disorder. Methods: This clinical trial is a randomized, placebo-controlled study (Registration: ChiCTR2300071025). It enrolled 39 adult patients diagnosed with depressive disorder, who were randomly assigned to either the placebo control group (n = 19) or the CCFM6432 intervention group (n = 20). The intervention period spanned four weeks. Assessments were conducted at both the beginning and end of the trial, including comprehensive questionnaire evaluations and the collection of serum and fecal samples. Results: In comparison to the placebo, treatment with CCFM6432 significantly decreased depression and anxiety scores, as well as ameliorated gastrointestinal dysfunction and poor sleep quality commonly associated with mood disorders. Microbiota analysis revealed an increase in species richness without notable changes in overall diversity, yet Pediococcus species was found to be more abundant post-treatment. Functional analysis indicated reduced activity in the NOD-like receptor signaling pathway, suggesting anti-inflammatory effects induced by the probiotic. Metabolomic profiling identified elevated levels of fecal lactic acid, which correlated with lower Hospital Anxiety and Depression Scale (HADS) scores, thereby linking probiotic metabolism to mood enhancement. Conclusion: These findings imply that CCFM6432 may improve brain function by modulating gut microbiota and their mediated immune homeostasis, underscoring its potential as an adjunctive treatment for mental disorders.