International review of neurobiologyAug 4, 2026

Gut bacteria and their role in brain decline and aging: how they work and possible treatments

Gut-Brain Axis Weekly Brief ↗PubMed ↗DOI ↗

Updated Aug 5, 2026

Abstract

Dysbiosis in the gut microbiota may play a crucial role in the development of neurodegenerative diseases and cognitive decline.

An imbalance in microbial composition and function is associated with neurodegenerative diseases.
The microbiota-gut-brain axis involves communication between gut microbes and the central nervous system through various pathways.
Gut dysbiosis is linked to specific conditions such as Alzheimer's disease, Parkinson's disease, and Multiple sclerosis.
Age-related changes in the microbiota may contribute to increased neuroinflammation and cognitive decline.
Therapeutic interventions targeting the microbiota, such as probiotics and dietary changes, are being evaluated for their potential to mitigate neurodegenerative pathology.

Simplified

The human gut microbiota represents a complex ecosystem of trillions of microorganisms with profound implications for neurological health. Emerging evidence demonstrates that dysbiosis, an imbalance in microbial composition and function, plays a crucial role in the pathogenesis of neurodegenerative diseases and age-related cognitive decline. This chapter summarizes current knowledge of the microbiota-gut-brain axis (MGBA) and elucidates how intestinal microbes and their metabolites communicate with the central nervous system via neural, immune, endocrine, and metabolic pathways. We examine the mechanistic links between gut dysbiosis and specific neurodegenerative conditions, including Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Multiple sclerosis (MS). Furthermore, we explore age-related changes in the microbiota and their contributions to neuroinflammation, immunosenescence, and cognitive decline. Finally, we evaluate therapeutic interventions targeting the microbiota, including probiotics, prebiotics, synbiotics, and dietary modulation as promising strategies to prevent and ameliorate neurodegenerative pathology. The chapter provides a comprehensive summary of how microbiota-targeted approaches may delay ageing and neurodegeneration.

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Gut bacteria and their role in brain decline and aging: how they work and possible treatments

Abstract

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