Alcohol and the Digestive System

The effects of alcohol on the liver are well known. But alcohol can affect not only the liver but many parts of the digestive system, beginning at the mouth and including the oesophagus, the stomach, the pancreas and the bowels.

These effects can vary with the amount of alcohol taken, how long it has been taken, the pattern of drinking, the person’s genetic characteristics, their nutritional state, their body weight, the medicines they take and any accompanying illnesses.

Regular drinking in large amounts in particular increases the risk of liver disease, pancreatitis and certain digestive cancers.

How does alcohol affect the digestive system?

Alcohol comes into direct contact with the digestive system, and after being absorbed it reaches the other organs by the blood — the liver chief among them.

Alcohol, and the acetaldehyde produced as it is broken down, can have harmful effects on tissue.

Long-standing drinking in large amounts can contribute to:

• Irritation and damage on the surface of the digestive system,
• Disturbance of the natural defence mechanisms of the cells,
• An increase in oxidative stress,
• Disturbance of the bowel barrier,
• Deficiencies of nutrients and vitamins,
• Damage to the liver and the pancreas,
• An increased risk of certain cancers developing.

Alcohol and reflux

Alcohol can increase gastro-oesophageal reflux complaints in some people.

By affecting the function of the muscular structure at the lower end of the oesophagus, it can make it easier for the contents of the stomach to pass back into the oesophagus.

The result may be that complaints such as:

• Burning in the chest,
• Bitter or sour fluid coming into the mouth,
• Belching,
• Burning in the throat

appear, or that existing complaints increase.

Because the effect of alcohol can vary from person to person, it may help for people whose reflux becomes marked after alcohol in particular to cut down or to stop.

Does alcohol harm the stomach?

Yes.

Alcohol can irritate the surface of the stomach directly. Drinking in large amounts or heavily in particular can cause damage to the lining of the stomach.

The result may be problems such as:

• Pain or burning in the stomach,
• Nausea,
• Vomiting,
• Loss of appetite,
• Gastritis.

Alcohol also matters in people with other risk factors for bleeding from the stomach and bowel.

Taking it together with NSAID painkillers such as aspirin, ibuprofen, naproxen or diclofenac in particular can increase both the harm to the lining of the stomach and the risk of bleeding.

Does alcohol cause ulcers?

The main causes of peptic ulcers are Helicobacter pylori infection and NSAID medicines.

For this reason it is not right to attribute every gastric or duodenal ulcer directly to alcohol.

But drinking in large amounts can damage the protective surface of the stomach and duodenum, can increase existing complaints, and can contribute to problems becoming worse, particularly in people with other risk factors.

Alcohol and cancer of the oesophagus

Alcohol is an important and modifiable risk factor, particularly for squamous cell cancer of the oesophagus.

The risk generally rises as the amount taken increases.

There is another very important point here:

Using alcohol and tobacco together increases the risk further still.

For this reason the total risk of cancers of the oesophagus and of the mouth and throat is higher in people who both smoke and drink.

Does alcohol affect the pancreas?

Yes. The pancreas is one of the organs that alcohol can affect considerably.

Drinking in large amounts is associated with the development of:

• Acute pancreatitis,
• Recurrent acute pancreatitis,
• Chronic pancreatitis.

Acute pancreatitis may present with severe pain beginning in the upper abdomen and spreading through to the back, with nausea and vomiting, and in some patients can run a serious course.

Long-standing drinking can contribute to chronic pancreatitis.

What happens in chronic pancreatitis?

As a result of long-standing damage to the pancreas, the normal structure and function of the organ may be disturbed.

The result may be:

• Constant or recurrent abdominal pain,
• Impaired digestion,
• Fatty, foul-smelling stools,
• Weight loss,
• Nutritional deficiency,
• Diabetes.

For a person with alcohol-related chronic pancreatitis, continuing to drink can contribute to the progression of the disease.

Because smoking is also an independent risk factor for chronic pancreatitis, stopping alcohol and tobacco together matters particularly.

How does alcohol affect the liver?

One of the most important effects of alcohol on the digestive system is seen in the liver.

The liver is the organ in which most of the alcohol taken is metabolised.

Long-standing drinking, or drinking in large amounts, can lead to damage in the liver at different levels that may follow one another:

fatty change → inflammation → fibrosis → cirrhosis

But this process does not advance at the same rate in every person.

Alcohol-related fatty liver

Drinking alcohol can cause fat to build up in the liver cells.

This is called alcohol-related fatty liver.

This stage mostly causes no symptoms and may be noticed by chance on blood tests or on ultrasound.

If alcohol is stopped early, the fatty change and part of the liver damage may regress.

What is alcohol-related hepatitis?

Long-standing heavy drinking can lead in some people to serious inflammation in the liver.

In this state there may be:

• Jaundice,
• Loss of appetite,
• Weakness,
• Nausea,
• Fever,
• Abdominal pain,
• Fluid collecting in the abdomen.

Severe alcohol-related hepatitis is a serious illness that can threaten life, and may need treatment in hospital.

Alcohol and cirrhosis

Liver damage continuing over many years can lead to permanent scarring in the liver. This is called cirrhosis.

Once cirrhosis has developed, serious complications may follow, such as:

• Ascites,
• Varices in the oesophagus and stomach,
• Bleeding from the digestive system,
• Changes in consciousness (hepatic encephalopathy),
• Jaundice,
• Liver failure,
• Liver cancer.

In a patient who has developed cirrhosis, stopping alcohol completely is extremely important for slowing the progression of the disease and improving survival.

Does alcohol increase the risk of liver cancer?

Yes.

Long-standing heavy drinking increases the risk of hepatocellular carcinoma (liver cancer), particularly where it has led to cirrhosis.

The presence of other risk factors such as hepatitis B, hepatitis C, obesity or metabolic liver disease can affect the total risk further still.

Does alcohol affect the bowels?

Yes.

Drinking in large amounts can affect the normal working of the bowels.

In some people there may be:

• Diarrhoea,
• Abdominal pain,
• Bloating,
• Changes in bowel movements.

Long-standing drinking in large amounts can also disturb the natural barrier of the bowel wall. As a result, the amount of certain substances passing from the bowel into the blood may increase, and this can become important particularly in people with liver disease.

Can alcohol cause nutritional deficiency?

Long-standing heavy drinking can lead to an inadequate and unbalanced diet.

Alcohol contains a great deal of energy but does not supply the protein, vitamins and minerals the body needs.

In heavy drinking, deficiencies can develop particularly in:

• Thiamine (vitamin B1),
• Folate,
• Vitamin B6,
• Magnesium.

Advanced liver or pancreatic disease can make the nutritional deficiency still more marked.

Does alcohol increase the risk of bowel cancer?

Yes.

Drinking alcohol is associated with an increased risk of colorectal cancer. The risk becomes more marked particularly as the amount taken increases.

Other factors also play a part in the development of colorectal cancer — age, family history, genetic characteristics, obesity, physical activity, diet and smoking.

Reducing alcohol therefore means removing one of the modifiable risk factors.

Which other digestive cancers is alcohol associated with?

Drinking alcohol is associated in particular with an increased risk of:

• Cancers of the mouth and throat,
• Cancer of the oesophagus,
• Liver cancer,
• Colorectal cancer.

The acetaldehyde produced as alcohol is broken down is a carcinogenic substance.

The important message about cancer risk is this:

as alcohol consumption falls, so does the risk.

There is no amount of alcohol that has been shown to carry no risk at all as far as cancer is concerned.

Is the idea that “a little alcohol is good for you” correct?

In the past it was suggested that drinking small amounts of alcohol might be protective, particularly against cardiovascular disease.

But a more cautious approach is taken to this today. It has become clear that some of the benefits seen in earlier observational studies may have arisen from lifestyle and other factors.

For this reason, starting to drink alcohol in order to gain health is not recommended.

As far as cancer in particular is concerned, the risk rises as consumption rises.

Who should avoid alcohol entirely?

For some people, not drinking alcohol matters particularly.

These include:

• Pregnant women,
• Children and adolescents,
• People with, or with a history of, an alcohol use disorder,
• People taking medicines that interact with alcohol,
• People who are going to drive or operate machinery.

Stopping alcohol completely also matters especially in conditions such as cirrhosis, alcohol-related liver disease and alcohol-related pancreatitis.

Does stopping alcohol help?

Yes.

In alcohol-related liver and pancreatic disease in particular, stopping alcohol is one of the most important parts of treatment.

When alcohol is stopped:

• Fatty liver may regress,
• Continuing damage in the liver may lessen,
• It may help to prevent recurrences of pancreatitis,
• The progression of cirrhosis may slow,
• The nutritional state may improve,
• The risk of some cancers may fall in the long term.

Even where advanced liver disease has developed, stopping alcohol can still bring important benefit.

The important message

Alcohol does not affect the liver alone. It can contribute to the development of disease in many organs of the digestive system.

Drinking in large amounts over a long period is associated with gastritis, pancreatitis, fatty liver, alcohol-related hepatitis, cirrhosis and certain digestive cancers.

The risk generally rises with the amount taken. Using alcohol and tobacco together in particular can raise the risk of certain digestive cancers further still.

In people with liver or pancreatic disease, stopping alcohol is not merely a preventive measure but usually an important part of treatment.

This content has been prepared for general information. Because the effects of drinking on a person’s health can vary with their accompanying illnesses, the medicines they take and the amount they drink, individual assessment should be made by a doctor.