Excessive alcohol use damages the tissues of the liver, producing a range of lesions, including fat deposits (steatosis), inflammation (hepatitis), and scarring (fibrosis and cirrhosis). Around 90% of heavy drinkers will develop the largely symptom-less fatty liver disease, while a third will see that progress to more damaging alcoholic hepatitis and 10% to 20% will develop cirrhosis, the irreversible scarring of the liver.
- Because the liver is essential to so many bodily processes, the effects of impaired liver function are wide-reaching and a potentially life-threatening impact of alcohol on health.
- Around a third of heavy drinkers will develop alcoholic hepatitis, usually after a decade or more of alcoholism. But it can also turn up following short-term binge drinking and in some moderate drinkers.
- Population-level studies have found the risk of liver disease increases markedly for men for drink more than 40g of ethanol per day and for women who consume more than 20g per day.
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What is alcoholic liver disease?
Alcoholic liver disease (ALD), also known as chronic liver disease, is an injury to the liver caused by long-term, excessive intake of alcohol, leading to an accumulation of fat, inflammation, and scarring of the liver. Because the liver is essential to so many bodily processes, the effects of impaired liver function are wide-reaching and a potentially life-threatening impact of alcohol on health.
There are three stages of alcoholic liver disease. Some heavy drinkers will experience them all.
1. Fatty liver
In fatty liver disease, too much fat builds up within hepatocytes (the main functional cells of the liver). This accumulation is known as fatty change or steatosis.
The liver is the main organ of lipid metabolism, and a certain amount of fat is stored in healthy livers. However, when large fatty globules appear and fat makes up 5% to 10% of the liver by weight, it’s an indication the liver is under strain. Severe fatty liver disease can cause inflammation, known as steatohepatitis. Hepatocytes balloon and become necrotic and through their deaths activate liver cells involved in the creation of scar tissue, or fibrosis. Extensive fibrosis can progress to cirrhosis.
More than 90% of heavy drinkers will develop fatty liver disease.[1] Even just a few days of heavy drinking can lead to fatty change.[2]
People who don’t drink can also develop abnormal fat deposits in their liver, in their case known as non-alcoholic fatty liver disease (NAFLD). Risk factors for NAFLD include obesity, type 2 diabetes, metabolic syndrome, genetics, and old age. Up to 75% of people who are overweight and up to 90% of those with severe obesity are thought to have fatty liver disease.[3][4]
2. Alcoholic hepatitis
Alcoholic hepatitis is the acute inflammation of the liver in response to alcoholic damage. Injured hepatocytes swell—a form of cell death called ballooning degeneration.
Around a third of heavy drinkers will develop alcoholic hepatitis, usually after a decade or more of alcoholism. But it can also turn up following short-term binge drinking and in some moderate drinkers.
With chronic inflammation, dying liver cells are replaced by scar tissue, leading to the next stage of liver disease.
3. Fibrosis/cirrhosis
Fatty liver disease and the inflammation of alcoholic hepatitis can contribute to scarring, known as fibrosis. The liver has a nearly miraculous ability to recover from acute injury, even severe injury, by creating new cells. However, when the damage is repeated or continuous, as in the case of excessive alcohol consumption, these attempts at regeneration produce only scar tissue—deposits of protein in the liver’s extracellular matrix.
Scar tissue performs none of the functions of the hepatocytes it replaces and can also deform the liver’s internal structure and obstruct blood flow to liver cells, leading to further cell death and scarring.[5]
Fibrosis can sometimes be reversed if a cause is identified and corrected, for instance, if the individual stops drinking. However, after a certain point, the fibrosis forms bands through the liver and becomes irreversible. This is cirrhosis: the shrinking and scarring of the liver, which can eventually lead to liver failure, advanced liver disease, and liver cancer.
There are other causes of cirrhosis: globally 57% of cases are attributed to chronic hepatitis B and hepatitis C infections.[6] However, in the US, where infection with hepatotropic viruses is relatively rare, around half of all cirrhosis deaths are attributable to alcohol.[7]
What causes alcoholic liver disease?
The liver is the primary site of ethanol metabolism and therefore sustains the most tissue damage from alcohol abuse of any place in the body.[8] However, only a third of heavy drinkers develop hepatitis and just 10 to 20% develop cirrhosis. Conversely, sometimes people who drink more moderately develop liver disease. This suggests the mechanisms of alcoholic damage to the liver are multi-factorial, with influence from genetics.
Alcohol likely causes liver damage by causing:
- the accumulation of toxic acetaldehyde, a metabolite of alcohol, in the liver. Acetaldehyde stimulates collagen deposition by liver cells. It’s also reactive and may lead to the build-up of other reactive substances in the liver.
- the secretion of inflammatory cytokines.
- oxidative stress: an excess of free radicals in the body, causing cell damage
- fatty acid synthesis in the liver and impaired fatty acid breakdown in the liver, converting the liver from an organ of fat burning to fat storage[9]
Risk factors
Some groups are more likely to develop alcohol-related liver disease when they drink.
Risk factors include:
- body composition: being overweight or obese alone can lead to liver damage, which compounds the injury caused by alcohol.
- Sex: women absorb and metabolize alcohol differently than men do and tolerate it less. The drinking threshold for developing liver disease is therefore lower for women.
- Ethnicity: rates of cirrhosis are higher for Hispanics and African Americans.
- Viral hepatitis: viral hepatitis, especially hepatitis C, can magnify the liver damage from alcohol.
- Family history: it’s unclear why vulnerability to alcoholic liver disease runs in families but some people may lack enzymes that help with the metabolism of alcohol.[11]
How much alcohol causes liver disease?
As people’s susceptibility to alcoholic liver disease varies, it’s impossible to determine how much drinking will lead to hepatitis, cirrhosis, liver failure, and death. Population-level studies have found the risk of liver disease increases markedly for men for drink more than 40g of ethanol per day and for women who consume more than 20g per day.
Cirrhosis usually requires drinking at least 80g/per day for at least 10 years. That’s the equivalent of 8 cans of beer, 6 shots of hard liquor, or 6 glasses of wine. When consumption exceeds 230g/day over 20 years, the risk of cirrhosis is 50/50.[10]
What are the symptoms of alcohol-induced liver disease?
Fatty liver disease is a silent disease, with few or no symptoms. Occasionally, people will experience
- fatigue
- pain in their liver, in the upper right of the abdomen
Alcoholic hepatitis is characterized by
- jaundice (yellow discoloration of the skin and whites of the eyes)
- abdominal swelling and tenderness
- nausea and vomiting
- lack of appetite
- ascites (fluid accumulated in the abdomen)
- hepatic encephalopathy, brain dysfunction caused by liver failure, featuring confusion, drowsiness, slurred speech, and personality and behavior changes
Cirrhosis causes
- jaundice
- easy bleeding and bruising
- swelling in the legs, feet, or ankles (edema)
- loss of appetite
- nausea
- weight loss
- itchy skin
- redness in the palms of the hands
- fluid accumulation in the abdomen (ascites)
- spiderlike blood vessels
- pale or white stool
- hepatic encephalopathy
- among women, absence or loss of menstrual periods
- among men, loss of sex drive, breast enlargement, and testicular atrophy[12]
How to prevent alcoholic liver disease
The best way to prevent alcoholic liver disease is to drink in moderation, if at all. Men under 65 should drink two drinks or fewer per day, while women and men over 65 should drink no more than one per day.
If you’re overweight, losing weight may reduce fat deposits in the liver. As viral hepatitis increases liver damage, you should protect yourself against infection. This means getting vaccinated against hepatitis B, not sharing needles or razors, and practicing safe sex.
You should also avoid taking medications that can harm the liver, especially acetaminophen (Tylenol).
How is alcoholic liver disease treated?
Unique among the body’s organs, the liver has a remarkable ability to regenerate, often quickly, when it's no longer under assault. With abstinence, fatty liver deposits can disappear and the damage from inflammation and even fibrosis can be reversed.
Even damaged livers can still work: when up to three-quarters of its hepatocytes have died, the liver can still function as normal.
Alcohol fatty liver disease is usually just treated with abstinence. However, excess weight may also be contributing to fatty deposits so once you’ve quit drinking you should try to lose weight through a combination of a healthy diet and exercise.
Alcoholic hepatitis is treated with:
- Nutritional supplementation, as many people dependent on alcohol are nutrient and calorie deficient.
- Medications that can reduce liver inflammation, such as corticosteroids and pentoxifylline
Liver damage from alcoholic cirrhosis can’t be reversed but its progression can be stopped or delayed through sobriety.
In addition, patients may be advised to:
- Eat a balanced diet, often with extra protein and calories to prevent the breakdown of muscles which may happen when your liver is unable to store fuel
- Avoid salt, which can increase edema (swelling) in the abdomen and legs
- Take diuretics, which may also reduce edema
- Take medication to address portal hypertension, a common complication of cirrhosis in which blood pressure in the main vein to the liver is elevated
- Use prescription creams to treat skin itching
In extreme cases of alcohol-related liver disease, patients may be required to go under the knife for partial or full liver transplants.
Alcoholic addiction treatment
Many people struggle to stop drinking alcohol safely and in the long term. Help is available, from medical detox to therapy to support groups. To find rehabs and treatment centers near you and begin your recovery, visit our rehab directory.
