A few possible gastrointestinal issues from alcohol use include:

  • impairment to the function of muscles separating the esophagus and stomach
  • damage to the mucosal lining of the esophagus, increasing risk of esophageal cancer
  • impeding secretion of gastric acids in the stomach
  • the impeding activity of muscles around the stomach
  • development of chronic diarrhea, caused by impairment to muscle movement in small and large intestines
  • stopping the flow of nutrients in small intestine/increase of toxins in intestinal lining—leading to alcohol-related damage

What Is The Gastrointestinal Tract?

The National Institute on Alcohol Abuse and Alcoholism (NIAAA) explains, “the GI tract can be viewed as one continuous tube extending from the mouth to the anus…which is subdivided into different segments with specific functions.”

The gastrointestinal tract consists of a number of organs, including the esophagus, stomach, and intestines. The gastrointestinal tract is not the digestive system but part of it. The digestive system consists of the GI tract as well as other organs involved in digestion, such as the tongue, salivary glands, and gallbladder.

The ways in which alcohol affects the gastrointestinal tract can be broken down into the different segments of the GI tract through which alcohol passes: oral cavity and esophagus, stomach, small intestine, and large intestine.

How Alcohol Affects The Gastrointestinal Tract

Alcohol, like many substances consumed by mouth, travels the normal route of the gastrointestinal tract before being absorbed into the bloodstream. In short, substances travel from the oral cavity (i.e., mouth) to the esophagus, on to the stomach, then to the small intestine where nutrients are gleaned, and finally to the large intestine where much of leftover waste is compacted.

Alcohol’s Effects On The Oral Cavity And Esophagus

The oral cavity and esophagus are two of the first parts of the body exposed to alcohol when a person drinks. That means alcohol has not been diluted in any way when it reaches these body parts, and the effects of alcohol are more direct.

People who drink heavily may experience mucosal injuries, such as lesions. Chronic alcohol abuse can also damage salivary glands, causing decreased production of saliva. Other effects of alcohol on the oral cavity and esophagus may include:

  • inflammation of the tongue and mouth
  • increased risk of tooth decay, gum disease, and teeth loss
  • a weakening of functioning of the esophagus, leading to increased acid reflux and/or heartburn and decreased ability to clear the acid
  • abnormal acid production
  • increased incidence of mucosal defects, such as inflammation and tearing

Alcohol’s Effects On The Stomach

The NIAAA reports that, even in small doses, alcohol “can alter gastric acid secretion, induce acute gastric mucosal injury, and interfere with gastric and intestinal motility.” The stomach is the first part of the body alcohol enters after passing through the oral cavity, so it is here where alcohol is broken down with gastric acid and enzymes.

Yet alcohol can affect adequate production of gastric acid. When people drink in moderation, it is less likely for them to experience decreased gastric acid. In fact, light to moderate drinking may stimulate gastric acid production. Heavy drinking and chronic drinking are the conditions which cause a decrease in gastric acid production.

The body needs gastric acid, not only to help break down food and substances but also to fight bacteria. Lessening the body’s ability to produce gastric acid effectively increases the chance of bacteria entering the small intestine.

How alcohol damages the gastric mucosa is unknown, but heavy alcohol use, even in a single incident, can cause inflammation and lesions in the mucosa. Heavy alcohol abuse can also affect how long it takes for alcohol to pass through the stomach to the intestines (gastric motility). This can lead to abdominal discomfort and bloating.

Alcohol’s Effects On The Small Intestine

The small intestine is where most nutrients are absorbed into the bloodstream. Alcohol can affect the absorption of certain nutrients. Alcohol can also disrupt the activity of some enzymes, which are responsible for functions throughout the small intestine.

Alcohol can also cause mucosal injury to the intestine, as with the stomach. Perhaps one of the largest risks of alcohol’s effects on the small intestine is that chronic or heavy alcohol use can make the intestine more permeable (easier to penetrate).

As the intestine becomes more permeable, the person struggling with heavy drinking experiences increased risk of bacteria and harmful toxins, such as endotoxins, entering the bloodstream and liver. This can lead to liver damage, which may be caused by an overgrowth of harmful bacteria due to increased permeability of the intestine as well as the rapid production of bacteria resulting from this process.

Alcohol’s Effects On The Large Intestine

While previous studies on the effects of alcohol did not focus largely on effects to the large intestine, the topic is beginning to receive more attention.

Many people who struggle with chronic alcohol abuse or alcoholism (both forms of alcohol use disorder), suffer from chronic diarrhea. Alcohol abuse can affect the time it takes for contents in the intestines to travel, thus affecting the time it takes for the large intestine to compact—and get rid of—waste. These and other effects of alcohol may contribute to chronic diarrhea.

Other Health Risks Of Alcohol

The gastrointestinal tract is not the only system in the body affected by alcohol abuse. In truth, alcohol abuse, especially heavy alcohol use or alcoholism, can affect all aspects of a person’s health.

Some other health risks of long-term alcohol abuse include:

  • Liver disease: Heavy, regular drinking can affect the liver’s metabolic rate, increased risk of alcoholic fatty liver disease, and can lead to long-term inflammation of the liver, or alcoholic hepatitis.
  • Pancreatitis: Pancreas inflammation which may require hospitalization.
  • Cancer: Heavy alcohol use increases the risk of development of several types of cancer, including cancer of the breast, throat, colon, rectum, liver, stomach, larynx, and esophagus.
  • Immune system: Chronic alcohol use may lead to a weakened immune system and lessened ability to fight off infection and infectious diseases.
  • Vitamin deficiencies: Alcohol affects the body’s ability to absorb nutrients and its rate of movement of substances within intestines, so vital nutrients may not be broken down the way the body needs them to be.
  • Brain damage: Alcohol interferes with the brain communication pathways, affecting mood, emotion, and bodily reactions.

Treatment For Alcohol Abuse

When alcohol abuse goes untreated, it can progress into addiction, a mental reliance, or dependence, a physical reliance. If a person becomes dependent on alcohol and tries to stop the use of it, they will likely experience withdrawal symptoms, some of which can be life-threatening.

A medically-assisted detoxification program for alcohol can help individuals with an alcohol use disorder overcome their dependence on alcohol so they can prepare for treatment. Many inpatient alcohol treatment centers include detox programs as part of their treatments.

For the best results and to help avoid relapse, detoxification should always be followed by formal treatment, which may include counseling, behavioral therapy, and a number of other treatments for alcohol as determined by individual need.