How common is fatty liver?

In the 1980s fatty liver was mainly seen in alcoholics or in those with excess alcohol consumption. Fatty liver is now recognised as the most common cause of abnormal liver function tests in the USA, UK and Australia. Around 20%, or one in five persons in the general population, in the USA and Australia has a fatty liver.

Fatty liver has been described for years, especially since the use of ultrasound scans; however it has previously been viewed as an uncommon cause of severe liver disease. This view is absolutely incorrect! The severe long term results of fatty liver disease are being seen increasingly in liver clinics all over the world.

Fatty liver is a very serious epidemic because it can, and is increasingly, affecting children. It can lead to obesity and diabetes and potentially cirrhosis and liver failure. Fatty liver will probably reduce your life span by many years and will greatly reduce your quality of life if left untreated.
Fatty liver will become the most common cause of severe liver disease and liver transplants.

• One in every 5 Australians and Americans has a fatty liver
• The incidence of Type 2 diabetes has tripled in the last 50 years, and nearly 20 million Americans suffer with this degenerative disease. This type of diabetes is often associated with liver dysfunction and in particular a fatty liver.
• Many people with chronic obesity have a fatty liver and it is not possible for them to lose weight efficiently, unless they first improve their liver function.

What is fatty liver?

Fatty liver is characterised by an excessive accumulation of fat in liver cells. It is the most common response to liver injury.

A fatty liver develops an excessive amount of fat, resulting in the normal, healthy liver tissue being partly replaced with areas of unhealthy fats. The fat starts to invade the liver, gradually infiltrating the healthy liver areas, so that less and less healthy liver tissue remains. This invasion of the liver by fat shares similarities with the way in which cancer tissue infiltrates the liver. The fatty liver has a yellow greasy appearance and is often enlarged and swollen with this fat. Fatty liver occurs when fat accumulation is more than 5% of the liver weight. The most common types of fat (lipids) to build up inside the liver cells are triglycerides. Fatty infiltration slows down the metabolism of body fat stores which means that the liver burns fat less efficiently, thus resulting in weight gain and inability to lose weight. However some people have a fatty liver without being overweight.

Fatty liver is known in medical circles as “Non-Alcoholic Fatty Liver Disease” and this is often abbreviated to NAFLD. The term NAFLD includes the condition of “simple fatty liver” but also incorporates the more severe inflammatory condition known as “Non-Alcoholic Steato-Hepatitis” also known as NASH.

NASH is a much more severe form of fatty liver than “simple fatty liver”, because in NASH there is much more liver inflammation, and this can easily progress to severe liver scarring and liver failure known as cirrhosis. It is interesting to know that NASH causes the same damage to the liver as that seen in severe alcoholics as proven with liver biopsy. The increased amounts of fat inside the liver cells cause inflammation of the liver and this is mediated by free radical oxidative stress on the liver cells.

Fatty liver is most commonly caused by incorrect diet, weight excess, obesity, alcoholism and diabetes. Other causes can include:

• Malnutrition- especially deficiency of protein and antioxidants
• Congenital metabolic disorders – (hereditary problems of metabolism recognised at birth or soon after)
• Excessive use or toxicity of prescribed medications (such as corticosteroids, valproic acid, tetracycline, salicylates and synthetic oestrogens)
• Exposure to toxic chemicals such as pesticides, insecticides, solvents, plastics, etc
• Infections of the liver