A comprehensive overview of the effects of probiotics, prebiotics and synbiotics on the gut-brain axis

Author: mycolabadmin
10/17/2025
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Summary

This comprehensive review examines how probiotics (beneficial live bacteria), prebiotics (food for beneficial bacteria), and synbiotics (combinations of both) can influence communication between the gut and brain. These interventions can produce beneficial compounds like GABA and serotonin, strengthen the gut barrier, and reduce inflammation, potentially helping with mood, anxiety, cognition, and various digestive disorders. However, effects vary greatly depending on the specific strain used, dosage, and individual differences in gut bacteria, and more large-scale studies are needed to confirm long-term clinical benefits.

Background

The gut-brain axis (GBA) represents a complex bidirectional communication system connecting the gastrointestinal tract and central nervous system through neural, endocrine, immune, and metabolic pathways. The gut microbiota comprises approximately 2000 bacterial species forming a complex ecosystem shaped by host genetics, diet, environment, and evolutionary history. Dysbiosis has been implicated in metabolic, immunological, and neurological conditions.

Objective

This narrative review systematically synthesizes current clinical and preclinical evidence on the role of probiotics, prebiotics, and synbiotics in regulating the gut-brain axis. The review aims to highlight mechanisms, therapeutic potential, limitations, and research gaps concerning these interventions’ effects on neurocognitive outcomes and systemic health.

Results

The review found that probiotics, prebiotics, and synbiotics can influence gut microbiota composition and modulate GBA function through neural, endocrine, immune, and metabolic pathways. Clinical evidence supports benefits for mood regulation, anxiety reduction, cognitive performance, gastrointestinal disorders, metabolic conditions, and immune homeostasis. However, effects are strain-specific, dose-dependent, and clinical efficacy remains inconsistent across conditions.

Conclusion

While probiotics, prebiotics, and synbiotics show promise as adjunctive approaches for CNS and systemic disorders, their clinical efficacy remains inconclusive due to methodological limitations, small sample sizes, and heterogeneous populations. Future investigations should focus on large-scale multicenter clinical trials, mechanistic studies, and standardized protocols to clarify pathways of action and define clinical relevance.

Published in:Frontiers in Microbiology,
Study Type:Narrative Review,
Source: PMID: 41178959, DOI: 10.3389/fmicb.2025.1651965