If fat accounts for more than 10 per cent of the liver’s weight, then this is known as ‘fatty liver’.
Fatty liver disease, sometimes called steatosis, is the build-up of excess fat in the liver cells.
It is normal for the liver to contain some fat. However, if fat accounts for more than 10 per cent of the liver’s weight, then this is known as ‘fatty liver’ and may lead to more serious health complications.
In many cases it is possible to reduce fatty liver disease with lifestyle changes, so detecting it early is important.
What is fatty liver disease?
Fatty liver disease is a common liver complaint in developed countries, affecting about one in every three people.
The liver has many important roles in the body including removing harmful substances from the blood stream and metabolising and storing nutrients from food. When fat builds up in the liver it can cause inflammation, scarring and cirrhosis of the liver which will stop it working properly.
Alcohol abuse abuse causes fatty liver, this is called alcoholic fatty liver disease (AFLD). It can lead to inflammation of the liver – a condition called steatohepatitis.
For everyone else who does not abuse alcohol, the condition is called non-alcoholic fatty liver disease or NAFLD.
NAFLD may not cause any damage to the liver but if inflammation does develop it is called non-alcoholic steatohepatitis, or NASH. NASH is one of the top three leading causes of cirrhosis.
If detected early, steps can be taken to manage NAFLD and reduce complications from it.
Fatty liver disease causes
Other possible causes include:
- Eating excess calories causes fat to build up in the liver and when the liver does not process and break down fats as it normally should, too much develops in the liver.
- People also tend to develop fatty liver if they have certain other conditions, such as diabetesor a high level of fat in their blood known as triglycerides.
- Alcohol abuse, rapid weight loss and malnutrition may also lead to fatty liver.
However, some people develop fatty liver even if they have none of these conditions.
Many specialists now also believe that metabolic syndrome – a cluster of disorders that increase the risk of diabetes, heart disease and stroke – plays an important role in the development of fatty liver.
Signs and symptoms of this syndrome include obesity, particularly around the waist (abdominal obesity), hypertension (high blood pressure), abnormal cholesterol levels and resistance to insulin, a hormone that helps to regulate the amount of sugar in the blood.
Of these factors, insulin resistance may be the most important trigger of NAFLD.
How does a liver become fatty?
Exactly how the liver becomes fatty is unclear. The fat may come from other parts of the body or the liver may absorb an increased amount of fat from your intestine.
Another possible explanation is that the liver loses its ability to change fat into a form that can be eliminated.
However, the eating of fatty foods by itself doesn’t produce a fatty liver.
Fatty liver disease symptoms
A fatty liver typically causes no symptoms on its own, so people often learn about their fatty liver when they have medical tests for other reasons.
NAFLD can damage your liver for years or even decades without causing any symptoms.
If the disease gets worse, and NASH or liver fibrosis (scarring) develop, you may experience fatigue, weight loss, abdominal discomfort, weakness and confusion. This can then progress to liver cirrhosis.
Fatty liver disease diagnosis
This can happen in a number of ways, but a typical one is that your doctor sees something unusual in a blood test or notices that your liver is slightly enlarged during a routine check-up.
These could be signs of a fatty liver.
To make sure you don’t have a different liver disease, your doctor may ask for more blood tests (including liver function tests), an ultrasound, a computer tomography (CT) scan or a medical resonance imaging (MRI) scan.
If other diseases are ruled out, then NAFLD may be diagnosed.
The only way to confirm the diagnosis is with a liver biopsy, where a doctor removes a sample of liver tissue with a needle and checks it under a microscope.
Fatty liver disease treatments
There are no medical or surgical treatments for fatty liver, but some steps may help prevent or reverse some of the damage.
- Losing weight can lower the amount of fat in your liver and reduce the inflammation in NASH. You should always lose weight – safely. This usually means losing no more than half to one kilogram (one to two pounds) a week.
- Aim to lower your triglycerides through diet, medication or both.
- Reduce or avoid alcohol completely.
- Control your diabetes (if you have it) by following the dietary advice, medication and check-up appointments your doctor has advised.
- Eat a balanced, healthy diet
- Increase your physical activity. Aim for 150 minutes per week of activity that makes you feel out of breath. Brisk walking is ideal. Start with a few minutes at a time and build up gradually.
- Stop smoking to reduce your risk of heart disease and strokes.
Medical treatments for fatty liver disease are currently the focus of intense research and doctors are studying whether various medications can help reduce liver inflammation.
These include new diabetes medications that may help you even if you don’t have diabetes.
In severe cases where liver failure has occurred then a liver transplant may be offered.