9 Chilling Effects of Alcohol on the Digestive System

Drinking too much alcohol can take a serious toll on your health. There are widely documented side effects on the brain, heart, liver, pancreas and immune system. There’s also an increased risk of cancer throughout the body.1 Multiple studies have investigated the long-term effects of alcohol on the digestive system. However, this topic has not been as widely covered in the mainstream media as other alcohol-related health repercussions.

What Is the Digestive System?

The digestive system is also called the gastrointestinal tract (or GI tract). It comprises:

  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine (colon)

These body parts also interact with the pancreas and liver, which can be severely damaged by long-term alcohol use.

The Effects of Alcohol on the Digestive System

Starting at the top of the GI tract, here is a summary of the devastating effects alcohol on the entire digestive system.

1. Oral Decay and Cancer

Heavy drinking can cause serious and permanent damage to a person’s mouth. Gum disease, tooth decay and mouth sores are all much more likely for heavy drinkers. Alcohol abuse is the second most common risk factor for oral cancer next to smoking. Alcohol causes a higher accumulation of plaque on the teeth, leading to the possibility of permanent tooth loss.

2. Esophageal Cancer

The biological mechanisms mediating alcohol-related cancer are not fully understood. However, we know alcoholic beverages contain at least 15 carcinogens. A carcinogen is any substance that can cause cancer. The carcinogens in alcoholic drinks include:

  • Acetaldehyde
  • Acrylamide
  • Aflatoxins
  • Arsenic
  • Benzene
  • Cadmium
  • Ethanol
  • Ethyl carbamate
  • Formaldehyde
  • Lead

The main carcinogen in the creation of alcohol is acetaldehyde. It occurs naturally in alcoholic beverages. Acetaldehyde produces carcinogenic effects on your body when you drink it. Specifically, it affects the upper aerodigestive tract. That means your pharynx, oral cavity, esophagus and larynx. Alcohol first contacts the oral cavity, followed by the esophagus. Therefore oral and esophageal cancers present the highest relative risks of alcohol-related cancer. In esophageal cancer, it does not appear to matter if a person drinks wine, beer or spirits. However, hard liquor more easily destroys the fine protective layer on the esophagus. In a meta-analysis of 222 studies comprising 92,000 light drinkers and 60,000 nondrinkers with cancer, light drinking was associated with a high risk of esophageal squamous cell carcinoma. This analysis showed an estimated 24,000 deaths from esophageal squamous cell carcinoma were attributable to light drinking. One has to keep in mind when alcohol use is self-reported, individuals may underestimate or under-report actual alcohol intake. That could mean higher drinking levels contributed to these cancer deaths.

3. Esophageal Variceal Hemorrhage

Esophageal varices (distended veins) impact the lower esophagus or the upper part of the stomach. This type of varices is particularly dangerous because increased pressure within the vein can cause them to burst, leading to a critical loss of blood. In people with alcohol- or obesity-related liver cirrhosis, varices can develop when blood flow through the liver is obstructed by scarring. The varices increase the pressure inside the portal vein, which carries blood from the intestines to the liver, a condition called portal hypertension. Esophageal variceal hemorrhage is a life-threatening complication associated with a much higher death rate than other causes of GI bleeding. Clinical factors associated with an increased risk of variceal bleeding include poor liver function and ongoing alcohol abuse. Some reports indicate variceal bleeding accounts for 11% to 20% of all upper GI bleeding, while 12 to 14 other studies suggest they are responsible for 50% to 80% of GI bleeding episodes. The estimated mortality rate for the first episode of variceal hemorrhage is 30% to 50%, which is dependent on the severity of the underlying liver disease. Individuals who experience one episode of bleeding from esophageal varices have a 60% to 80% chance of re-bleeding within one year of the initial episode. Approximately one-third of recurrent bleeding episodes are fatal. A retrospective study analyzed 45 sudden fatal death cases (28 men and 17 women) involving esophageal variceal hemorrhage outside the hospital setting. All of the deceased were white, with an age range of 24 to 72 (average age 50.6 years). Ruptured esophageal varices were located in the lower third of the esophagus in 44 cases. Cirrhosis of the liver was present in all cases, of which 42 were alcohol-related based on a known history of chronic alcohol consumption. A hepatocellular carcinoma was found in three cases. Alcohol-induced pancreatic tissue alterations were frequently found and 30 toxicology reports were positive for alcohol in blood and urine samples. Of the 45 cases, 37 deaths were attributed to esophageal variceal rupture alone. The remaining eight deaths were attributed to a combination of severe loss of blood and the following coexisting diseases: five cases of decompensated diabetes and one each of bronchopneumonia, dilated cardiomyopathy and acute hemorrhagic pancreatitis.

4. Gastrointestinal Bleeding

Gastrointestinal bleeding (GIB) is a common and potentially life threatening medical problem accounting for more than 200,000 inpatient admissions and 7,000 deaths in the U.S. annually. Most studies of non-variceal bleeding have focused on peptic ulcers, with conflicting findings linking bleeding to alcohol consumption. A large-scale study involving men indicated the risk of GIB increased with the amount of liquor consumed. After adjusting for other potential risk factors, individuals who consumed five or more alcoholic drinks per week had an increased risk of GIB compared to those who consumed liquor less than once per month. The risk of GIB was also higher among men who consumed alcohol without meals compared to those who drank with meals. Alcohol consumption coupled with regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) and/or aspirin increased the risk of GIB. In general, men who consumed more alcohol were more likely to be a current or past smoker and be regular users of aspirin or NSAIDs. Neither past nor current smoking appeared to have a significant effect on GIB risk.

5. Peptic Ulcer

In the last decade, the decreasing prevalence of Helicobacter pylori (H. pylori) infection and improvement of peptic ulcer treatment such as proton pump inhibitors has reduced the incidence of uncomplicated peptic ulcer disease. In the same time frame, however, several studies indicate peptic ulcer disease has not decreased. Limited studies have examined the association between aging or alcohol consumption and complicated peptic ulcer disease. A Korean study involving 396 individuals (average age 50.6) diagnosed with perforated peptic ulcer (PPU) revealed 47% consumed alcohol (more than 20 g of alcohol a week) and 55.8% had a smoking habit. Older age and alcohol consumption were significant risk factors for PPU not associated with H. pylori or NSAIDs.

6. Alcoholic Gastritis

Gastritis is inflammation of the lining of the stomach. As a whole it is largely preventable and treatable. Acute gastritis may present with an array of symptoms, the most common being nondescript abdominal discomfort. Additional symptoms include nausea, vomiting, loss of appetite, belching and bloating. Alcohol is an irritant that causes inflammatory changes in the gastric mucosa. Evidence of H. pylori infection is found in 20% of individuals younger than 40 and 50% of individuals older than 60. Alcoholic gastritis is most associated with hard liquor such as whisky, vodka and gin. Complications of acute gastritis include bleeding from an erosion or ulcer, gastric outlet obstruction, dehydration from vomiting and renal insufficiency as a result of dehydration.

7. Acid Reflux

Gastroesophageal reflux disease, commonly referred to as GERD, is one of the most common disorders. GERD has been on the rise over the last two decades. Alcohol consumption may increase symptoms of GERD and cause damage to the esophageal mucosa. Individuals with symptomatic GERD are often advised to avoid alcohol consumption or to consume moderate amounts of alcohol to help alleviate symptoms. The scientific evidence linking GERD to more general alcohol consumption has been inconsistent. Although the association is not clear, researchers hypothesize multiple factors may contribute to the potential GERD/alcohol connection, including esophageal and gastric muscosal damage. Some of these changes may also be due to the toxic effects of metabolized acetaldehyde.

8. Gastric Cancer

Gastric cancer, also known as stomach cancer, is one of the most prevalent cancers. Thankfully, worldwide mortality rates have declined rapidly over the past few decades. The American Cancer Society estimated 28,000 people in the U.S. would be diagnosed with stomach cancer in 2017 and about 10,960 will die from the disease. The relationship between alcoholic beverages and gastric cancer is biologically plausible because ethanol is fat soluble and can damage the gastric mucosa. Moreover, acetaldehyde can have a local toxic effect, which could be a potential contributing factor in the development of gastric cancer. A meta-analytic study investigated the alcohol-gastric cancer connection including comparative risk in moderate and heavy drinkers and dose-dependent risk. The analysis of 10 studies confirmed that alcohol consumption can increase the risk of gastric cancer even at lower levels of consumption.

9. Colorectal Cancer

A meta-analysis of 57 studies examined the association between alcohol consumption and colorectal cancer risk. The study showed people who regularly drank 50 or more grams of alcohol per day (approximately 3.5 drinks) had a 1.5 increased risk of developing colorectal cancer as nondrinkers or occasional drinkers. For every 10 grams of alcohol consumed per day, there was a 7% increase in the risk of colorectal cancer.

10. Diarrhea and Vomiting

Diarrhea and vomiting are two of the classic symptoms of a hangover. They also occur the earliest stage of alcohol withdrawal or alcohol-related inflammation of the GI tract.


Alcohol causes diarrhea by:

  • Causing the stomach to produce more acid than normal
  • Inhibiting absorption of water from the large intestine
  • Decreasing digestive enzymes
  • Speed up the passage of stools


Vomiting is an alcohol-related sign of several conditions:

  • alcohol poisoning
  • excessive drinking
  • a hangover
  • alcohol withdrawal

It’s Not Worth the Effects of Alcohol on the Digestive System

Clearly, alcohol wreaks havoc on every part of the body including the digestive system. If you’re struggling with multiple effects of alcohol on your digestive system, it’s likely you’re struggling with a much bigger problem. Alcoholism can sneak up on you. Although chronic alcohol consumption may have already wreaked damage on your body, it’s not too late to seek treatment and stop drinking.

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