Non-alcoholic fatty liver disease (NAFLD)

You’re at an increased risk of NAFLD if you:

Liver Disease

There are many types of liver disease. Some of the most common types are treatable with diet and lifestyle changes, while others may require lifelong medication to manage. If you begin treatment early enough, you can often prevent permanent damage. But you may not have symptoms in the early stages. Late-stage liver disease is more complicated to treat.

Overview

What is liver disease?

Your liver is a large and powerful organ that performs hundreds of essential functions in your body. One of its most important functions is filtering toxins from your blood. While your liver is well-equipped for this job, its role as a filter makes it vulnerable to the toxins it processes. Too many toxins can overwhelm your liver’s resources and ability to function. This can happen temporarily or over a long period of time.

When healthcare providers refer to liver disease, they’re usually referring to chronic conditions that do progressive damage to your liver over time. Viral infections, toxic poisoning and certain metabolic conditions are among the common causes of chronic liver disease. Your liver has great regenerative powers, but constantly working overtime to restore itself takes its toll. Eventually, it can’t keep up.

What are the stages of chronic liver disease?

Chronic liver disease progresses in roughly four stages:

1. Hepatitis.
2. Fibrosis.
3. Cirrhosis.
4. Liver failure.

Stage 1: Hepatitis

Hepatitis means inflammation in your liver tissues. Inflammation is your liver’s response to injury or toxicity. It’s an attempt to purge infections and start the healing process. Acute hepatitis (an immediate and temporary response) often accomplishes this. But when the injury or toxicity continues, so does the inflammation. Chronic hepatitis causes hyperactive healing that eventually results in scarring (fibrosis).

Stage 2: Fibrosis

Fibrosis is a gradual stiffening of your liver as thin bands of scar tissue gradually add up. Scar tissue reduces blood flow through your liver, which reduces its access to oxygen and nutrients. This is how your liver’s vitality begins to gradually decline. Remarkably, some amount of fibrosis is reversible. Your liver cells can regenerate, and scarring can diminish if the damage slows down enough for it to recover.

Stage 3: Cirrhosis

Cirrhosis is severe, permanent scarring in your liver. This is the stage where fibrosis is no longer reversible. When your liver no longer has enough healthy cells left to work with, its tissues can no longer regenerate. But you can still slow or stop the damage at this stage. Cirrhosis will begin to affect your liver function, but your body will attempt to compensate for the loss, so you might not notice at first.

Stage 4: Liver failure

Liver failure begins when your liver can no longer function adequately for your body’s needs. This is also called “decompensated cirrhosis” — your body can no longer compensate for the losses. As liver functions begin to break down, you’ll begin to feel the effects throughout your body. Chronic liver failure is a gradual process, but it is eventually fatal without a liver transplant. You need a liver to live.

How common is liver disease?

Approximately 1.8% of U.S. adults (4.5 million adults) have liver disease. It causes about 57,000 U.S. deaths a year. Globally, it causes about 2 million deaths per year, or 4% of all deaths. Deaths are mostly from complications of cirrhosis, with acute liver failure accounting for a small portion. Liver disease affects men and people assigned male at birth (AMAB) twice as often as women and people assigned female at birth (AFAB).

Non-alcoholic fatty liver disease (NAFLD)

Early-stage NAFLD does not usually cause any harm, but it can lead to serious liver damage, including cirrhosis, if it gets worse.

Having high levels of fat in your liver is also associated with an increased risk of serious health problems, such as diabetes, high blood pressure and kidney disease.

If you already have diabetes, NAFLD increases your chance of developing heart problems.

If detected and managed at an early stage, it’s possible to stop NAFLD getting worse and reduce the amount of fat in your liver.

Stages of non-alcoholic fatty liver disease (NAFLD)

NAFLD develops in 4 main stages.

Most people will only ever develop the first stage, usually without realising it.

In a small number of cases, it can progress and eventually lead to liver damage if not detected and managed.

The main stages of NAFLD are:

1. simple fatty liver (steatosis) – a largely harmless build-up of fat in the liver cells that may only be diagnosed during tests carried out for another reason
2. non-alcoholic steatohepatitis (NASH) – a more serious form of NAFLD, where the liver has become inflamed
3. fibrosis – where persistent inflammation causes scar tissue around the liver and nearby blood vessels, but the liver is still able to function normally
4. cirrhosis – the most severe stage, occurring after years of inflammation, where the liver shrinks and becomes scarred and lumpy; this damage is permanent and can lead to liver failure (where your liver stops working properly) and liver cancer

It can take years for fibrosis or cirrhosis to develop. It’s important to make lifestyle changes to prevent the condition getting worse.

Am I at risk of non-alcoholic fatty liver disease (NAFLD)?

You’re at an increased risk of NAFLD if you:

• are obese or overweight – particularly if you have a lot of fat around your waist (an “apple-like” body shape)
• have type 2 diabetes
• have a condition that affects how your body uses insulin
• are insulin resistance, such as polycystic ovary syndrome
• have an underactive thyroid
• have high blood pressure
• have high cholesterol
• have metabolic syndrome (a combination of diabetes, high blood pressure and obesity)
• are over the age of 50
• smoke

But NAFLD has been diagnosed in people without any of these risk factors, including young children.

Although it’s very similar to alcohol-related liver disease (ARLD), NAFLD is not caused by drinking too much alcohol.

Symptoms of non-alcoholic fatty liver disease (NAFLD)

There are not usually any symptoms of NAFLD in the early stages. You probably will not know you have it unless it’s diagnosed during tests carried out for another reason.

Occasionally, people with NASH or fibrosis (more advanced stages of NAFLD) may experience:

• a dull or aching pain in the top right of the tummy (over the lower right side of the ribs)
• extreme tiredness
• unexplained weight loss
• weakness

If cirrhosis (the most advanced stage) develops, you can get more severe symptoms, such as yellowing of the skin and the whites of the eyes (jaundice), itchy skin, and swelling in the legs, ankles, feet or tummy (oedema).

See a GP urgently or call 111 if you have any of these symptoms and have a liver condition.

How non-alcoholic fatty liver disease (NAFLD) is diagnosed

NAFLD is often diagnosed after a blood test called a liver function test produces an abnormal result and other liver conditions, such as hepatitis, are ruled out.

But blood tests do not always pick up NAFLD.

The condition may also be spotted during an ultrasound scan of your tummy.

This is a type of scan where sound waves are used to create an image of the inside of your body.

If you’re diagnosed with NAFLD, further tests may be needed to determine which stage you have. This may involve a special blood test or having another type of ultrasound scan (Fibroscan).

Some people may also need a biopsy, where a small sample of liver tissue is taken using a needle so it can be analysed in a laboratory.

Children and young people with an increased risk of NAFLD (those with type 2 diabetes or metabolic syndrome) should have an ultrasound scan of their liver every 3 years.

Other tests you may have include a CT scan or MRI scan.

Treatment for non-alcoholic fatty liver disease (NAFLD)

Most people with NAFLD will not develop any serious problems, but if you’re diagnosed with the condition it’s a good idea to take steps to stop it getting any worse.

There’s currently no specific medication for NAFLD, but making healthy lifestyle choices can help.

Treatment also may be recommended for associated conditions (high blood pressure, diabetes and cholesterol) or complications.

You may be advised to have regular appointments with your doctor to check your liver function and look for signs of any new problems.

Medicines

There’s not currently any medicine that can treat NAFLD, but various medicines can be useful in managing the problems associated with the condition.

Liver transplant

If you develop severe cirrhosis and your liver stops working properly, you may need to be put on the waiting list for a liver transplant.

Or it may be possible to have a transplant using a section of liver removed from a living donor.

As the liver can regenerate itself, both the transplanted section and the remaining section of the donor’s liver are able to regrow to a normal size.

Things you can do if you have non-alcoholic fatty liver disease (NAFLD)

Adopting a healthy lifestyle is the main way of managing NAFLD.

For example, it can help to:

• lose weight – you should aim for a BMI of 18.5 to 24.9 (use the BMI calculator to work out your BMI); losing more than 10% of your weight can remove some fat from the liver and improve NASH if you have it
• eat a healthy diet – try to have a balanced diet high in fruits, vegetables, protein and carbohydrates, but low in fat, sugar and salt; eating smaller portions of food can help, too
• have water instead of sweet drinks
• exercise regularly – aim to do at least 150 minutes of moderate-intensity activity, such as walking or cycling, a week; all types of exercise can help improve NAFLD, even if you do not lose weight
• stop smoking – if you smoke, stopping can help reduce your risk of problems such as heart attacks and strokes

NAFLD is not caused by alcohol, but drinking may make it worse. It’s therefore advisable to cut down or stop drinking alcohol.

Page last reviewed: 13 January 2022
Next review due: 13 January 2025

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