Effects of Ethanol on the Digestive System: A Narrative Review

Alcohol consumption is responsible for approximately 6% of all deaths and 5.1% of the global disease burden. The most common alcohol-related causes of death include liver cirrhosis (50% of cases), pancreatitis (25%), and esophageal cancer (22%). In this review, we provide an overview of ethanol metabolism and highlight the major diseases caused by alcohol consumption in the liver and gastrointestinal tract. Due to its central metabolic role, the liver is particularly susceptible to ethanol, which is known to cause a wide spectrum of conditions, including steatosis, steatohepatitis, alcohol-associated hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma). The gastrointestinal tract is often one of the first areas to show signs of damage from excessive alcohol consumption. Chronic alcohol abuse is a well-established risk factor for both acute and chronic pancreatitis, as well as pancreatic cancer. Approximately 70% of acute pancreatitis cases and 30% of chronic pancreatitis cases are attributable to alcohol abuse. Epidemiological studies have consistently demonstrated a positive correlation between alcohol intake and the prevalence of gallstones. Moreover, alcohol is an important risk factor for gastroenteropancreatic cancer, as ethanol metabolism produces acetaldehyde, a potent carcinogen for humans. In conclusion, chronic ethanol intake, through one of its main metabolic products, acetaldehyde, causes pathological changes in the gastrointestinal tract, liver, pancreas, and gallblad- der. Even moderate amounts of alcohol may increase the risk of cancers, such as colorectal cancer. Therefore, if there is clinical suspicion of excessive alcohol intake in a patient with persistent digestive symptoms (e.g., abdominal pain, nausea, vomiting, diarrhea, and bloody stools), immediate medical evaluation is essential. Referral to specialized centers with expertise in alcohol use disorder is a key management option for patients with established alcohol use disorder.