Prolonged Intestinal Ethanol Absorption and Oxidative Stress: Revisiting the Gut–Liver Axis in Alcohol-Associated Disease

Chronic alcohol consumption induces oxidative stress not only in the liver but also in the gastrointestinal tract, where prolonged intestinal ethanol absorption plays a pivotal and underrecognized role. This review reframes ethanol pharmacokinetics to emphasize sustained jejunal and ileal uptake, which maintains elevated blood alcohol levels and perpetuates redox imbalance across the gut–liver axis. We integrate recent findings on ethanol-induced barrier dysfunction, CYP2E1-mediated ROS production, microbial dysbiosis, and mitochondrial disruption, proposing that the intestine is an active site of injury and a driver of systemic inflammation. Key mechanistic insights reveal that gut-derived endotoxins, compromised epithelial integrity, and microbiome–mitochondria interactions converge to exacerbate hepatic and extrahepatic damage. We further explore emerging therapeutic strategies—ranging from NAD+ repletion and probiotics to fecal microbiota transplantation—that target this upstream pathology. Recognizing prolonged intestinal ethanol absorption as a clinically meaningful phase offers new directions for early intervention and redox-based treatment in alcohol-associated disease.