Alcohol and neurodegenerative diseases: a review of mechanistic insights and disease specific effects.

Background: Neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD) represent a significant global public health problem. Alcohol consumption is a common lifestyle factor that has been implicated as both a risk factor and potential modifier of disease progression.Objectives: This review integrates evidence from human and experimental studies to characterize the effects of alcohol consumption on the onset and progression of major neurodegenerative diseases.Methods: A narrative review was undertaken examining the pathophysiological effects of alcohol on the brain and its disease-specific effects on neurodegenerative disorders, integrating findings from human cohort studies and mechanistic investigations in preclinical models.Results: Experimental evidence indicates that chronic alcohol consumption exacerbates neurodegeneration through multiple converging mechanisms, including oxidative stress, mitochondrial dysfunction, lipid peroxidation, inflammatory signaling, disruption of neurotrophic pathways, impairment of dopaminergic neurotransmission, and alcohol-induced gut microbiota dysbiosis with blood-brain barrier compromise. Epidemiological data suggest dose-dependent and disease-specific associations, with heavy and sustained consumption more consistently linked to increased risk or accelerated progression of AD and PD, while evidence in ALS and HD remains inconsistent.Conclusion: Alcohol exerts a multifaceted and context-dependent influence on neurodegenerative diseases. Accumulating evidence supports that long-term heavy alcohol consumption is associated with enhanced neurodegeneration. Minimizing alcohol consumption may present a pragmatic opportunity to reduce neurodegenerative risk.