Nonalcoholic fatty liver disease (NAFLD) is an umbrella term for a range of liver conditions affecting people who drink little to no alcohol. As the name implies, the main characteristic of NAFLD is too much fat stored in liver cells.
NAFLD is increasingly common around the world, especially in Western nations. In the United States, it is the most common form of chronic liver disease, affecting about one-quarter of the population.
Some individuals with NAFLD can develop nonalcoholic steatohepatitis (NASH), an aggressive form of fatty liver disease, which is marked by liver inflammation and may progress to advanced scarring (cirrhosis) and liver failure. This damage is similar to the damage caused by heavy alcohol use.
Compared with a normal liver (left), a fatty liver (right) appears enlarged and discolored. Tissue samples reveal fat deposits in nonalcoholic fatty liver disease, while inflammation and advanced scarring (cirrhosis) are visible in nonalcoholic steatohepatitis.
NAFLD usually causes no signs and symptoms. When it does, they may include:
Possible signs and symptoms of NASH and advanced scarring (cirrhosis) include:
Make an appointment with your doctor if you have persistent signs and symptoms that cause you concern.
The liver is your largest internal organ. About the size of a football, it's located mainly in the upper right portion of your abdomen, beneath the diaphragm and above your stomach.
Experts don't know exactly why some people accumulate fat in the liver while others do not. Similarly, there is limited understanding of why some fatty livers develop inflammation that progresses to cirrhosis.
NAFLD and NASH are both linked to the following:
These combined health problems appear to promote the deposit of fat in the liver. For some people, this excess fat acts as a toxin to liver cells, causing liver inflammation and NASH, which may lead to a buildup of scar tissue in the liver.
A wide range of diseases and conditions can increase your risk of NAFLD, including:
NASH is more likely in these groups:
It is difficult to distinguish NAFLD from NASH without further testing.
The main complication of NAFLD and NASH is cirrhosis, which is late-stage scarring in the liver. Cirrhosis occurs in response to liver injury, such as the inflammation in NASH. As the liver tries to halt inflammation, it produces areas of scarring (fibrosis). With continued inflammation, fibrosis spreads to take up more and more liver tissue.
If the process isn't interrupted, cirrhosis can lead to:
Between 5% and 12% of people with NASH will progress to cirrhosis.
A normal liver (left) shows no signs of scarring. In cirrhosis (right), scar tissue replaces normal liver tissue.
Esophageal varices are enlarged veins in the esophagus. They're often due to obstructed blood flow through the portal vein, which carries blood from the intestine, pancreas and spleen to the liver.
Liver cancer begins in the cells of the liver. The most common form of liver cancer begins in cells called hepatocytes and is called hepatocellular carcinoma.
To reduce your risk of NAFLD:
Because NAFLD causes no symptoms in most cases, it frequently comes to medical attention when tests done for other reasons point to a liver problem. This can happen if your liver looks unusual on ultrasound or if you have an abnormal liver enzyme test.
Tests done to pinpoint the diagnosis and determine disease severity include:
Imaging procedures used to diagnose NAFLD include:
If other tests are inconclusive, your doctor may recommend a procedure to remove a sample of tissue from your liver (liver biopsy). The tissue sample is examined in a laboratory to look for signs of inflammation and scarring.
A liver biopsy can be uncomfortable, and it does have small risks that your doctor will review with you in detail. This procedure is performed by a needle insertion through the abdominal wall and into the liver.
The first line of treatment is usually weight loss through a combination of a healthy diet and exercise. Losing weight addresses the conditions that contribute to NAFLD. Ideally, a loss of 10% of body weight is desirable, but improvement in risk factors can become apparent if you lose even 3% to 5% of your starting weight. Weight-loss surgery is also an option for those who need to lose a great deal of weight.
For those who have cirrhosis due to NASH, liver transplantation may be an option.
No drug treatment has been approved by the Food and Drug Administration for nonalcoholic fatty liver disease, but a few drugs are being studied with promising results.
With your doctor's help, you can take steps to control your nonalcoholic fatty liver disease. You can:
No alternative medicine treatments are proved to cure nonalcoholic fatty liver disease. But researchers are studying whether some natural compounds could be helpful, such as:
Vitamin E. In theory, vitamin E and other vitamins called antioxidants could help protect the liver by reducing or neutralizing the damage caused by inflammation. But more research is needed.
Some evidence suggests vitamin E supplements may be helpful for people with liver damage caused by nonalcoholic fatty liver disease. But vitamin E has been linked with increased risk of death and, in men, an increased risk of prostate cancer.
Coffee. In studies of people with nonalcoholic fatty liver disease, those who reported drinking two or more cups of coffee a day had less liver damage than those who drank little or no coffee. It's not yet clear how coffee may influence liver damage, but findings suggest it may contain certain compounds that may play a role in fighting inflammation.
If you already drink coffee, these results may make you feel better about your morning cup of coffee. But if you don't already drink coffee, this probably isn't a good reason to start. Discuss the potential benefits of coffee with your doctor.
Start by making an appointment with your family doctor or primary doctor if you have signs and symptoms that worry you. If your doctor suspects you may have a liver problem, such as nonalcoholic fatty liver disease, you may be referred to a doctor who specializes in the liver (hepatologist).
Because appointments can be brief, it's a good idea to be well prepared. Here's some information to help you get ready, and what to expect from your doctor.
If you find out you have nonalcoholic fatty liver disease, some basic questions to ask include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
Your doctor is likely to ask you a number of questions, such as: