Plain language summary
Major depressive disorder (MDD) may be improved using psychobiotics. These supplements which contain either gut microbiota or ingredients which support their growth may have positive effects on mental health. However their exact effects on MDD are still to be determined. This post-hoc analysis of a randomised control trial aimed to determine the effects of psychobiotics on MDD in 110 patients over 8 weeks. The results showed that probiotics increased levels of the brain protein, brain-derived neurotrophic factor (BDNF), which was associated with decreased symptoms of depression. Prebiotics marginally decreased levels of BDNF. It was concluded that probiotics decreased symptoms of depression by possibly increasing levels of the brain protein BDNF in individuals suffering from MDD. This study could be used by healthcare professionals to recommend a probiotic to individuals with MDD to improve symptoms.
Abstract
Background/Aims: Psychobiotics are probiotics or prebiotics that, upon ingestion in adequate amounts, yield positive influence on mental health via microbiota-gut-brain axis regulation to modulate the circulating cytokines, chemokines, neurotransmitters, or neurotrophins levels. We have recently shown that a psychobiotic combination (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175; CEREBIOME) significantly improved depression symptoms in patients with depression. Recent animal data suggest the influence of the gut microbiota on brain-derived neurotrophic factor (BDNF), which was shown to correlate with antidepressant response in depressive patients. Therefore, we conducted this exploratory post hoc analysis of BDNF levels to clarify the mechanism of action of this psychobiotic in our cohort. Methods: Our study was a double-blind, randomized controlled trial of patients with low-to-moderate depression receiving either a probiotic combination, prebiotic or placebo. From the 110 patients randomized in the trial, 78 were included in this post hoc analysis (probiotic, n = 28; prebiotic and placebo, n = 25). We compared serum BDNF levels from participants at baseline and endpoint, and assessed the Pearson correlation between depression severity and BDNF levels for each intervention. Results: We found that post-intervention BDNF levels were significantly different between groups (P < 0.001). Furthermore, BDNF levels increased significantly in the probiotic group compared to both the prebiotic (P < 0.001) and placebo groups (P = 0.021), which inversely correlated with depression severity compared to placebo (ANOVA/ANCOVA, P = 0.012; Pearson, r = -0.79, P < 0.001). In the prebiotic group, BDNF levels reduced but not significantly compared with placebo group (P > 0.05). Conclusion: Eight-week supplementation with B. longum and L. helveticus in depressive patients improved depression symptoms, possibly by increasing BDNF levels.
Methodological quality
Jadad score
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5
Allocation concealment
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No
