Role of Bifidobacterium spp. intake in improving depressive mood and well-being and its link to kynurenine blood level: an interventional study.

ABSTRACT

OBJECTIVES: Evidence for the contribution of the brain-gut-microbiota axis to the depression pathophysiology is increasing nowadays. Disturbed gut microbiota equilibrium along with bad dietary habits both lead to kynurenine pathway abnormalities contributing to the depression pathophysiology. In this respect, many studies are found but the interventional clinical trials are limited. The present interventional study aims to evaluate the impact of Bifidobacterium spp. supplementation together with improving dietary intake on depressive mood and well-being and their correlation with kynurenine blood level in adult Egyptian healthy volunteers. METHODS: A number of 98 healthy female volunteers with a mean age of 46.96 ± 1.82 years were selected and enrolled in this study. They were given yogurt enriched with Bifidobacterium spp. daily for eight weeks. Clinical examination as well as questionnaires for the evaluation of psychological well-being and depression were done at base line and after eight weeks of intervention. Fasting blood samples and stool samples were collected from all subjects at baseline and eight weeks after the intervention for the investigation of serum kynurenine concentration, blood hemoglobin, serum transaminases (ALT & AST) serum urea and creatinine as well as fecal Bifidobacterium count. RESULTS: Data revealed that both depression and well-being showed highly significant improvement combined with significant drop in kynurenine blood level after intervention. Also, a significant rise in fecal Bifidobacterium count and a significant improvement in hemoglobin level and activity of liver enzymes were recorded. After intervention, a significant negative correlation was recorded between depression and fecal Bifidobacterium count as well as between serum kynurenine level, and well-being. CONCLUSION: Bifidobacterium spp. supplementation combined with improvement in dietary intake resulted in improvement of depressive mood and well-being and reduced kynurenine blood level.