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What are Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic steatohepatitis (NASH)?

NAFLD is a term that is used to describe a range of conditions that are caused by a build-up of fat in the liver; which is not caused by drinking excess alcohol. It is normal for the liver to store some fat but if this exceeds 5-10% of the weight of the liver it can start to cause problems. NAFLD is a major cause of liver disease and now accounts for over 60% of liver patients in Western countries. 

In the early stages of NAFLD deposits of fat begin to build up within the cells of the liver. This is often referred to as 'fatty liver' or the medical term, steatosis. It is largely harmless and usually goes unnoticed because it does not tend to cause any symptoms. 

In some people fatty liver can progress to a more serious condition called Non-Alcoholic Steatohepatitis (NASH) where inflammation begins to form in and around the fatty liver cells.

Over a long period of time persistent inflammation causes scar tissue around the liver and nearby blood vessels known as fibrosis. Even at this stage of the condition the liver is still able to function normally.

If the amount of scar tissue continues to increase it can eventually become so extensive that it will prevent the liver from being able to function normally. This is known as cirrhosis.

It can take years for fibrosis or cirrhosis to develop. If you are at risk it is important to get tested so that if a positive diagnosis is confirmed you can make lifestyle changes as early on as possible to prevent the disease from progressing.

Who typically gets NAFLD and NASH?

The majority of people with NAFLD are overweight (this is defined as having a BMI of over 25). However, not everyone who is overweight or obese will develop a fatty liver and not everyone who has a fatty liver is overweight.

Calculate your BMI here.

People are more likely to develop NAFLD if they have any of the following risk factors:

  • type 2 diabetes
  • high blood pressure
  • high cholesterol
  • smoker

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

What are the symptoms of NAFLD and NASH?

In the early stages of NAFLD there often aren’t any symptoms. You may not even know you have it unless it is diagnosed during tests carried out for another reason.

People who go on to develop the more advanced stages of the disease (NASH) may experience:

  • abdominal pain (especially over the lower right side of the ribs)
  • fatigue (extreme tiredness)
  • nausea
  • loss of appetite
  • unexplained weight loss
  • weakness

If the most advanced stage (cirrhosis) develops, you may experience more severe symptoms, such as,

  • jaundice (yellowing of the skin and the eyes)
  • itchy skin
  • swelling in the abdomen, legs, ankles or feet.

Click here to read more about the symptoms of cirrhosis.

How are NAFLD and NASH diagnosed?

Diagnosis is often made via a blood test called a Liver Function Test (LFT). This test measures levels of enzymes and proteins which indicate how well the liver is working. When the results of this test are judged to be abnormal it can indicate a problem in the liver. However, even if you have NAFLD the results of this test may still show that the liver is working normally.

An ultrasound scan can indicate whether there is a higher than normal level of fat in the liver.

A Fibroscan (a specialist type of ultrasound) measures the stiffness of the liver tissue which can help to assess the level of fibrosis and can indicate whether or not cirrhosis is present. A liver biopsy can give a more precise assessment of liver health and determines whether NAFLD has progressed to NASH.

What is the treatment for NAFLD and NASH?

There are no medical treatments currently available for NAFLD. Following a healthy lifestyle can prevent any existing liver damage from getting worse and may even help to reverse the damage.

NICE guidelines recommend that: “Losing weight and exercising more can help people with NAFLD. Many people find that these simple changes can help NAFLD improve or stop it getting worse.

Are there support groups for NAFLD/NASH patients?

Information and support are available from:

The NASH Education Program

The Fatty Liver Foundation

What do patients with NAFLD/NASH say about LiverMultiScan?

Click here to read an account from a patient with NAFLD who took part in the Patient LiverMultiScan study.