Microbial Bioactives | Online ISSN 2209-2161
Volume 8 Number 1 2025
REVIEWS (Open Access)
Probiotics and the Gut–Brain Connection on Microbial Pathways Supporting Mental Well-Being - A Systematic Review
Christine Maranhão Ribeiro 1*, Thaís Regina Rodrigues Vieira 1
Microbial Bioactives 8 (1) 1-8 https://doi.org/10.25163/microbbioacts.8110470
Submitted: 04 August 2025 Revised: 01 October 2025 Accepted: 07 October 2025 Published: 09 October 2025
Abstract
The growing recognition of the gut–brain axis has reshaped how we understand emotional and cognitive health. Instead of viewing anxiety, depression, and stress-related conditions solely as neurological challenges, research now highlights the profound influence of the gut’s microbial community on mental well-being. This systematic review brings together recent experimental, clinical, and meta-analytical studies to explore how probiotics support this complex communication network. By examining literature across major scientific databases, the review traces the neural, immune, and hormonal pathways through which gut microbes affect mood and cognition. A consistent theme across studies is the role of gut dysbiosis in disrupting neurotransmitter activity, elevating inflammation, and weakening stress-response mechanisms. In contrast, probiotic supplementation—most notably strains from Lactobacillus and Bifidobacterium—appears to restore balance by enhancing serotonin production, strengthening the gut barrier, and lowering cortisol levels. These changes translate into noticeable improvements in anxiety and depressive symptoms, along with better cognitive performance in both animal models and human trials. Yet, applying these findings broadly remains complex. Individual differences in microbiome composition, variations in probiotic strains and doses, and uncertainties about long-term effects create challenges for universal recommendations. Even so, one message stands out: diet plays a central role in nurturing a healthy gut ecosystem. Embracing probiotic-rich foods and mindful eating habits may offer a gentle, natural path to supporting emotional resilience. Ultimately, probiotics present a promising and accessible addition to holistic mental health strategies, encouraging a deeper appreciation of how nurturing the gut can nurture the mind.
Keywords: Gut–brain axis, probiotics, microbiota, mental health, anxiety, depression, cognition, neuroinflammation, dietary modulation.
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