Microbiome Dysbiosis as a Driver of Neurodegeneration: Insights into Alzheimer’s and Parkinson’s Diseases

Microbiome dysbiosis—an imbalance in gut microbial communities—has emerged as a critical factor in the pathogenesis of neurological disorders, particularly Alzheimer’s and Parkinson’s diseases. This review examines the role of gut microbiota in neurodegeneration, emphasizing how dysbiosis disrupts gut–brain communication through mechanisms such as impaired gut permeability, systemic inflammation, and neuroinflammation. The gastrointestinal and central nervous systems interact bidirectionally, with microbial metabolites like short-chain fatty acids playing a pivotal role in maintaining gut and brain health. Dysbiotic shifts in microbial composition can compromise the blood–brain barrier, enabling inflammatory molecules to alter brain biochemistry and potentially accelerate neurodegenerative processes. Additionally, this review explores therapeutic strategies—including probiotics, prebiotics, and dietary modifications—designed to restore microbial balance, reduce neuroinflammation, and slow disease progression. Further research is essential to refine microbiome-targeted therapies and fully elucidate their potential in managing neurodegenerative diseases.