ALCOHOL AND THE DIGESTIVE SYSTEM / GASTROINTESTINAL TRACT

You bring the bottle up to your lips and tilt your head back allowing the poison to enter your body.  Your mouth is the opening to the gastrointestinal (GI) tract.  Guzzling down alcohol interferes with all parts of the gastrointestinal tract.  With the first sip, you are injuring the tissues in your mouth and esophagus.  The liquid inflicts further injury as it flows into your stomach and then into the small intestines. Alcohol requires no digestion—once in the body, it enters the bloodstream immediately through the stomach or small intestine lining. If you just ate something, the process slows down, but you will still become intoxicated and damage will still occur.

 

Chronic alcohol use leads to detrimental consequences in the GI tract.  The sooner you stop using alcohol, the greater your chances are of avoiding the extremely painful and possibly deadly effects alcohol has on the GI tract.

 

What is the GI tract and what are its functions?

§         The GI tract’s job is to physically and chemically break down the food that you eat.  The GI tract allows absorption of nutrients into bloodstream and excretes any waste products it generates.

§         Direct contact of alcohol with the mucus membrane that lines upper GI tract can cause numerous metabolic and functional changes.  Metabolic changes have to do with the chemical processes that take place in living organisms, resulting in growth, generation of energy, elimination of wastes, and other body functions as they relate to the distribution of nutrients in the blood after digestion.

What happens in the oral cavity and the esophagus when they are habitually exposed to alcohol?

Figure 1.  Lower esophageal sphincter (LES) is shown at junction between esophagus and stomach.  After drinking it becomes weak and thus may allow gastric acids from the stomach, which are used to digest food,  into the esophagus.

 

Chronic alcohol abuse causes:

·        Damage to the salivary glands, which interferes with saliva secretion.

·        An enlargement of the parotid gland, one of the largest pairs of salivary glands that lie at the side of the face just below and in front of the external ear.

·        Inflammation of the tongue and mouth.  (Whether due to poor nutrition or alcohol’s direct effect on the mucus membranes is unknown).

·        Increased incidence of tooth decay, gum disease, and loss of teeth.

·        Impairment to movement of the esophagus.

Even a single drinking episode significantly weakens the lower esophageal sphincter (LES) (See figure 1).  Thus, gastroesophageal reflux, backflow of contents of the stomach into the esophagus that is often the result of incompetence of the lower esophageal sphincter, may occur and the ability of the esophagus to clear refluxed gastric acid is reduced.  This effect of alcohol on the LES is one of the causes of heartburn.

Some of the diseases of the oral cavity and esophagus related to heavy alcohol consumption are:

 

Figure 2.  Carcinoma of the tongue with associated white lesions

 

·        Oral cancer:  Cells invade and destroy normal tissue cells on the lips and in the mouth and upper throat. (see figure 2)

·        Barrett’s esophagus: The lining of esophagus is replaced by abnormal cells which leads to abnormal acid production.  This is a precancerous condition.

·        Gastoesophageal reflux disease (GERD) The sphincter weakens or relaxes, and the contents of the stomach splash back up into the esophagus.

·        Esophageal stricture: Cells lining the esophagus are damaged and cause narrowing of the opening.  A person with this condition will have trouble swallowing foods.

·        Gastrointestinal bleeding: Any blood loss that occurs through the digestive tract.

·        Gastritis:  The inflammation of the lining of the stomach.

·        Esophageal Cancer: A tumor that grows in the lining of the esophagus (See figures 3-5)

·        “Nutcracker esophagus”: This disease mimics symptoms of coronary heart disease.

·        Mallory-Weiss syndrome: The massive bleeding caused by tears in the mucosa at the junction of the esophagus and the stomach.

·        Esophageal varices:  A bleeding condition resulting from dilated veins in the walls of the lower part of the esophagus and, sometimes, the upper part of the stomach.

Figure3.  This is a picture of the normal esophagus.

Figure 4. This is what happens when a person develops Barrett’s esophagus.

 

 

 

Figure 5. This is a esophageal polyps, which are linked to Barrett’s Esophagus.  Fig 5 taken from Gut Feelings.  South Denver Gastroenterology

 

Figure 3 & 4. From Atlas of Gastrointestinal

Endoscopy  A. Freytag M. Kutscha

 

 

How is your stomach affected by alcohol?

Even moderate drinking can still cause changes in gastric acid secretion, cause acute gastric mucosal injury, and also interfere with gastric and intestinal motility.

What exactly is Gastric Acid Secretion, and how does alcohol affect it?

·        Gastric secretions of hydrochloric acid and of the enzyme pepsin in the stomach begin protein digestion.

·        Alcohol consumption affects gastric acid secretion.  In low to moderate doses it stimulates gastric acid secretion—in higher doses it causes inhibition.

·        Chronic alcohol consumption causes shrinkage of gastric mucosa and decreased gastric secretory capacity.  Thus the stomach has less ability to kill bacteria that enter the body with food, which may lead to the colonization of the upper small intestine with potentially harmful organisms.

What is gastric mucosal injury?

§         Chronic alcohol use causes bleeding gastric lesions that can destroy parts of the mucosa.

§         Even a single episode of heavy drinking can induce mucosal inflammation and hemorrhagic lesions.

What does Alcohol do to the stomach muscle?

§         Alcohol causes damage to the muscle layers of the stomach wall which mix incoming food bolus with gastric fluids.

§         Use of alcohol can cause decreased GI smooth muscle contraction.

§         After chronic use of alcohol, there is an increase in propulsive contractions, which causes diarrhea.

What are the effects of alcohol on gastric and intestinal motility?

Alcohol causes damage to the muscles that surround the stomach, and this damage changes how long it takes food to go through these organs.  Depending on alcohol concentration and accompanying meals, inhibition of gastric motility can occur and thus delay the emptying of stomach. This will lead to bacterial degradation of food and the production of gasses, which may lead to fullness and abdominal discomfort.

How does alcohol affect the small intestine?

§         The small intestine is the organ where most nutrients are absorbed into the bloodstream. 

§         Alcohol causes interference with absorption of nutrients. 

§         It can also interfere with enzymes needed for digestion, with the transportation of nutrients from intestine to bloodstream, and with enzymes needed to metabolize drugs and other foreign organic substances in the gut. 

§         Alcohol causes mucosal damage even in healthy people during a single drinking episode and can cause erosions and bleeding.  

§         Alcohol also causes an increase in intestinal permeability which lets large molecules that normally would not be able to cross the intestinal wall to get through. 

§         There is also the possibility of overgrowth of normal bacterial flora.

§         Alcohol decreases the muscle movements that keep food for further digestion, which may cause increased sensitivity to foods with high sugar content as well as causing shortened transit time and diarrhea often found in alcoholics.

 

How does alcohol affect the large intestine?

 

·        In healthy humans, alcohol consumption significantly reduces the frequency and strength of the muscle contractions in the segment of the rectum, which could reduce transit time of intestinal contents and contribute to diarrhea frequently observed in alcoholics.

 

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