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Effect of probiotic and prebiotic vs placebo on psychological outcomes in patients with major depressive disorder: A randomized clinical trial

A. Kazemi, A. Noorbala, K. Azam, M. Eskandari, K. Djafarian

Clinical Nutrition, 2019

81 participants · 453 citations

Abstract

BACKGROUND

Disturbance in the equilibrium of the gut microbiota has been involved in the pathophysiology of depression. Probiotics have the potential to healthfully modulate the gut microbiome. Prebiotics could also be effective by stimulation of growth of some bacterial species in the gut microbiota.

OBJECTIVE

The aim of this double blind clinical trial, was to compare the effect of supplementation with the probiotic and prebiotic on the Beck Depression Inventory (BDI) score as a primary outcome as well as the kynurenine/tryptophan ratio and tryptophan/branch chain amino acids (BCAAs) ratio as secondary outcomes in patients with major depressive disorder (MDD).

DESIGN

One hundred and ten depressed patients were randomly assigned to receive the probiotic (Lactobacillus helveticus and Bifidobacterium longum), prebiotic (galactooligosaccharide) or placebo for 8 weeks. Serum tryptophan and BCAAs were measured by HPLC, and kynurenine by ELISA kit. Dietary intake and physical activity of the participants were recorded at baseline.

RESULTS

A total of 81 subjects (aged 36.5 ± 8.03 y; mean (95% CI), 2.27 (1.76-2.93) y of depression duration) completed the trial (28 in the probiotic group, 27 in the prebiotic group, and 26 in the placebo group). From baseline to 8 weeks, probiotic supplementation resulted in a significant decrease in BDI score (17.39-9.1) compared to the placebo (18.18-15.55) and prebiotic (19.72-14.14) supplementation (p = 0.042). Inter-group comparison indicated no…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 81 participants or records.

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