A comprehensive narrative review has detailed the multifaceted damaging effects of alcohol consumption on the digestive system, emphasizing that approximately 6% of all deaths worldwide are attributable to alcohol consumption.

In the review, published in the Journal of Translational Gastroenterology, investigators emphasized that more than 50% of alcohol-related deaths in both male and female patients may be caused by gastrointestinal diseases, with the most common causes being liver cirrhosis (50%), pancreatitis (25%), and esophageal cancer (22%).

"Chronic ethanol intake, through one of its main metabolic products, acetaldehyde, causes pathologic changes in the gastrointestinal tract, liver, pancreas, and gallbladder," the study authors wrote. "Even moderate amounts of alcohol may increase the risk of cancers such as colorectal cancer," they emphasized.

The investigators, led by Fabio Caputo, detailed how alcohol is absorbed in the upper digestive tract (20% in the stomach and 75% in the first part of the small intestine), with the remaining 5% absorbed in the small intestine and colon. The liver metabolizes approximately 90% of absorbed alcohol, converting ethanol to acetaldehyde via alcohol dehydrogenase (ADH).

According to the review, the damage resulting from alcohol consumption is influenced by multiple factors, including dose and duration of abuse, genetic predisposition, environmental factors, gender, and nutritional status. The Dionysos study, referenced in the article, demonstrated that the increased risk of developing alcoholic liver disease and cirrhosis occured with alcohol consumption exceeding 30 g/day for at least 10 years, with the risk increasing linearly with higher intake.

The investigators emphasized the higher susceptibility of female individuals to alcohol-related damage, noting that "women have higher blood alcohol levels than men after consuming similar doses of alcohol (adjusted for body weight)." This difference was found to be attributed to lower body water content and reduced first-pass metabolism as a result of decreased gastric ADH enzyme activity.

The review detailed the spectrum of alcohol-associated liver diseases, including steatosis (the most common manifestation, observed in 60% to 100% of heavy drinkers), alcoholic steatohepatitis (10% to 35% of cases), alcohol-associated hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma.

Beyond the liver, the investigators documented alcohol's effects throughout the gastrointestinal tract, including:

• Oral cavity: Stomatitis and periodontal disease
• Esophagus: Gastroesophageal reflux disease, acute and chronic esophagitis, Barrett's esophagus, and Mallory-Weiss syndrome
• Stomach: Superficial gastritis, chronic atrophic gastritis, and hemorrhagic gastritis
• Intestines: Increased intestinal permeability ("leaky gut"), dysbiosis, malabsorption, and altered intestinal motility
• Pancreas: Acute and chronic pancreatitis, with approximately 70% of acute pancreatitis cases and 30% of chronic pancreatitis cases attributable to alcohol misuse
• Gallbladder: Increased risk of gallstones and cholecystitis.

The review also highlighted alcohol's carcinogenic potential, noting: "Alcohol is an important risk factor for gastrointestinal tumors, as ethanol metabolism produces acetaldehyde, a potent carcinogen for humans." The investigators outlined the main processes involved in acetaldehyde-induced carcinogenesis, including direct damage to DNA strands, inhibition of DNA repair mechanisms, and shortening of telomere length.

"It is recommended that individuals maintain minimal alcohol intake (ie, social drinking, which is up to one drink per day for women and up to two drinks per day for men) and seek immediate medical evaluation if they are suspected of excessive alcohol intake and experience persistent digestive symptoms," the study authors underscored.

The review represented a significant contribution to understanding the comprehensive impact of alcohol on digestive health, consolidating knowledge on metabolic pathways and clinical manifestations across the entire digestive system.

Disclosures can be found in the review.