What is fatty liver?

• Answer : simply what the name suggests - too much fat in the liver!

• Some important facts:
  • Fatty liver is the accumulation of fat (mainly as triglycerides) within liver cells.
  • This happens when the fat coming into the liver is more than the fat going out (the liver makes and secretes fat).
  • This condition is becoming more common.
  • It is the commonest cause of abnormal liver enzyme tests (blood tests for the liver). This is because fat in the liver may cause some inflammation.

What causes fatty liver?

• Excess alcohol intake may be the main underlying cause.

  • How much is too much?

  • Refer also to section on alcohol and liver.

  • The risk of moderate alcohol intake (2 standard drinks per day; less than 20g) causing significvant fatty liver is 5-fold for non-obese men, 15-fold for overweight men and 35-fold for obese men.
    

  • Obesity and even moderate alcohol intake not good for the liver!!!

  • Safe limit may only be 3 standard drinks per week  - better to be nil

• There are an increasing number of people with fatty liver that is NOT caused by alcohol.
  • This condition has an association with being overweight, having diabetes (or pre-diabetes - also called impaired glucose tolerance -  and having raised cholesterol or raised triglyceride levels in the blood.

• The underlying problem is considered to be "insulin resistance".
  • This means that the body is not responding normally to the insulin hormone.
  • This problem directly relates to the amount of fat tissue in the body.
  • Fatty tissue is not inert. It secretes a range of hormones that control the body's metabolism.
  • Insulin resistance promotes increased rate of delivery of fat to the liver from the tissues.
  • Insulin resistance (and therefore fatty liver) is primarily determined by body weight and also the level of physical activity.

  • Fatty liver is a marker for significant insulin resistance and is associated with a 2- to 5-fold risk of developing type 2 diabetes

  • The main risk to health with fatty liver is not severe liver disease but diabetes, heart disease and stroke - all long term consequences of insulin resistance / metabolic syndrome

• Fatty liver is more common some ethnic groups.
  • That is, for a given weight there is more fatty liver in some groups.
  • It is more common with Indian and Chinese compared with European groups.
  • It is also more common in Pacific Islanders.

• About 10% of people with excess fat in the liver will develop inflammation in the liver.
  • The medical term is called steatohepatitis.
  • This sometimes abbreviated as NASH - non-alcohol steatohepatitis.
  • Another abbreviation is NAFLD (non-alcoholic fatty liver disease).

• This inflammatory process, if sustained over a long period of time, can lead to significant liver fibrosis and eventually to cirrhosis (severe liver damage).
  • The risk is low (compared to other causes of liver disease).
  • Overall only 2% will progress to cirrhosis.  This is a much smaller risk than for fatty liver caused by alcohol alone
  • The risk is higher with type 2 diabetes
  • The risk is higher with obesity AND moderate alcohol (or greater) alcohol intake