Fatty liver, or steatosis, is a broad term that describes the buildup of fats in the liver. Having fat in your liver is normal, but if more than five to 10 percent is fat, then it is called fatty liver disease.
Fatty liver is a reversible condition and usually goes away on its own. Fatty liver often has no symptoms and does not cause any permanent damage.
The liver is the second largest organ in the body. The liver’s function is to process everything we eat or drink and filter any harmful substances from the blood. If too much fat has accumulated in the liver then this process is interfered with. The liver commonly repairs itself by rebuilding new liver cells when the old ones are damaged. When there is repeated damage to the liver, permanent scarring takes place. This is called cirrhosis.
Fatty liver is quite common. Ten to 20 percent of Americans have too much fat in their liver, but no inflammation or damage is present. Most cases of fatty liver are detected between ages 50 and 60. When fatty liver is caused by an underlying condition, it can become harmful to the liver if the cause is not recognized and treated.
There are typically no symptoms of fatty liver. Some people experience fatigue or vague abdominal discomfort. The liver may become slightly enlarged—which your doctor will notice with a thorough physical exam.
If the liver has become inflamed, there may be other symptoms, such as poor appetite, weight loss, and feeling extremely weak, sick, or tired.
The most common cause is alcoholism. Almost all heavy drinkers have fatty liver disease. Other causes are toxins, certain drugs, and inherited metabolic disorders. In many cases, doctors are not exactly sure what causes fatty liver in people who aren’t alcoholics, but it has been associated with high blood cholesterol, obesity, and type 2 diabetes.
Fatty liver develops when the body creates too much fat or cannot metabolize fat fast enough. As a result, the leftover is stored in liver cells where it accumulates to become fatty liver disease. Eating a high-fat diet does not directly result in fatty liver.
Besides alcoholism, other common causes of fatty liver include:
- metabolic syndrome
- excess body weight
- insulin resistance (type 2 diabetes)
- high levels of triglycerides (fats) in the blood
- viruses (hepatitis A, etc.)
There are four types of fatty liver:
Nonalcoholic Fatty Liver
Nonalcoholic fatty liver (NAFL) develops when the liver has difficulty breaking down fats, which causes a buildup in the liver tissue. The cause is not related to alcohol. NAFL is diagnosed when more than 10 percent of the liver is fat.
Alcoholic Fatty Liver
Alcoholic fatty liver is the earliest stage of alcohol-related liver disease. The liver is damaged by heavy drinking and unable to break down fats. If the patient abstains from alcohol, the fatty liver will go away. Within six weeks of being alcohol-free, the fat will disappear. However, if excessive alcohol use continues, cirrhosis may develop.
Nonalcoholic Steatohepatitis (NASH)
When the fat builds up enough, it will cause the liver to swell. If the original cause is not from alcohol, it is called NASH. This disease can impair liver function. Symptoms can be seen with this disease, such as loss of appetite, nausea, vomiting, abdominal pain, and yellowing of the skin. If left untreated, NASH can progress to permanent scarring of the liver and eventual liver failure.
Acute Fatty Liver of Pregnancy
This is a rare complication of pregnancy that can be life threatening. Symptoms begin in the third trimester and include persistent nausea and vomiting, pain in the upper-right abdomen, jaundice, and general malaise. Women who are pregnant will be screened for this condition. Most women improve after delivery and have no lasting effects.
Since fatty liver is the buildup of extra fats in the liver, it is more likely to develop if you are overweight or obese.
Other factors that may increase your risk for fatty liver are:
- excessive alcohol use (drinking large amounts of alcohol can damage your liver)
- excessive use of over-the-counter medication (taking more than the recommended doses of certain medications, such as acetaminophen, can increase your risk of fatty liver)
- type 2 diabetes (fat accumulation in the liver has been linked to insulin resistance, the most common cause of type 2 diabetes)
- high cholesterol
- high triglyceride levels
- metabolic syndrome
If the liver has become inflamed, your physician can detect it by examining the abdomen. An extensive history may reveal fatigue or loss of appetite as well. A thorough history will include alcohol use and other medications or supplements.
Higher than normal liver enzymes may be found on a routine blood test. This does not confirm a diagnosis of fatty liver. Further analysis will look for the cause of inflammation.
The fat on your liver will show up as a white area on the image. Other imaging studies may be done as well such as a CT (computed tomography) scan or MRI (magnetic resonance imaging). Imaging studies can detect fat in the liver, but will not be able to confirm any further damage.
A needle is inserted into the liver to remove a piece of tissue for examination (after giving a local anesthetic to lessen the pain). This is the only way to know for certain if you have fatty liver. The biopsy will also help your doctor learn the exact cause.
Treatment focuses on the factors that may cause the disease. Common interventions center around:
- treatment of alcoholism
- cholesterol management
- weight loss
- blood sugar control
To reduce your risk of fatty liver, make healthy lifestyle choices, such as:
- Limit or avoid alcohol consumption.
- Choose a healthy diet.
- Maintain a healthy weight.
Most cases of fatty liver are harmless and will not lead to progressive liver disease. If the cause is related to high cholesterol, diabetes, or obesity, then treating the cause will reverse the fatty liver process.
If the cause is alcoholism, cessation of drinking may allow the liver to heal completely. A biopsy can determine if there is permanent damage, how bad is the damage, and how it needs to be treated.