Non-alcoholic fatty liver disease (NAFLD) or fatty liver refers to the excessive accumulation of lipid within the liver.  NAFLD is increasingly common in the Western World, and in most countries is the leading cause of liver disease. 

What is fatty liver?

Fatty liver occurs when too much fat (lipid) accumulates within liver cells (hepatocytes) called non-alcoholic fatty liver (NAFL).  Over time, greater fat accumulation can result in inflammation that damages the liver cells, called non-alcoholic steatohepatitis (NASH).  This can lead to fibrosis, or scaring within the liver, that eventually leads to cirrhosis (severe scaring in the liver) and liver cancer (hepatocellular carcinoma).  

Why do people get fatty liver?

Fatty liver develops for many reasons, including,

  • Obesity
  • Insulin resistance 
  • Central adiposity (central abdominal fat)
  • High intake of refined carbohydrates
  • Consumption of fructose containing drinks

Do people with fatty liver develop symptoms?

Most people with fatty liver are asymptomatic.  The presence of increased fat within the liver is usually diagnosed incidentally during radiological imaging by USS, CT or MRI. This is usually characterised by a generalised reduction in the density of the liver.  Occasionally there may be islands of fatty sparing that present as focal liver lesions that need to be further characterised by MRI.  In the early stages liver enzyme blood tests may be entirely normal.  If NAFLD progresses to NASH or cirrhosis symptoms of liver failure may develop.

How do you diagnose fatty liver?

One should suspect NAFLD in patients with metabolic syndrome (obesity, insulin resistance, hypertension and hyperlipidaemia) with an aberration in liver enzyme profile.  Exclusion of other potential causes of liver disease including excess alcohol consumption, viral hepatitis and autoimmune liver disease is required.  Radiological imaging by USS, CT and MRI can show fatty accumulation within the liver.  Ultrasound elastography, a non-invasive test, can assess the severity of steatosis as well as presence or absence of fibrosis.  The gold standard remains liver biopsy that both quantifies the amount of fat as well as the presence or absence of liver damage.  

What is the treatment for NAFLD?

Treatment of fatty liver is primarily around improving ones metabolic profile; losing weight, increasing physical activity, restricting intake of refined carbohydrates and optimising blood pressure, glucose control and lipid profile. Patients should completely abstain from alcohol even if this isn’t considered a contributor to their liver disease.  A reduction of 8% in body weight has been shown to significantly improve patients liver enzyme profile and total fat within the liver.  This can be achieved through a combination of caloric restriction and increased physical exercise.  Both Mediterranean and very low-carbohydrate diets have been shown to reduce fat within the liver.  Strength training, endurance exercise or either high or low intensity interval training have been shown to reduce fat within the liver, as long as it is performed consistently.  There are a number of different drug therapies that are being investigated for the treatment of fatty liver disease.