Non-Alcoholic Fatty Liver Disease
What is non-alcoholic fatty liver disease (NAFLD)?
Fatty liver disease (steatosis) occurs when your body begins storing fat in your liver. Some fat in your liver is normal, but when more than 10% of your liver’s weight is fat, it may begin to suffer. Excessive alcohol use is one common reason for fatty liver disease. But many people develop it without excessive alcohol use. This is called non-alcoholic fatty liver disease (NAFLD).
How common is this condition?
NAFLD affects up to 25% of people worldwide. Most people won’t have symptoms, and some may never know they have the condition. But 2% to 5% of people will experience complications from the fat in their liver. When fat leads to inflammation and cell damage in your liver, it’s called steatohepatitis. The non-alcoholic version is called non-alcoholic steatohepatitis (NASH).
Who does non-alcoholic fatty liver disease affect?
It can affect anyone, including all ages and races. But it's more common in people of Hispanic descent and less common in Black people. Middle age, weight and diabetes are also commonly associated with NAFLD. For example, up to 75% of people who have obesity or diabetes, and up to 90% of people who have advanced or class III obesity have NAFLD.
Symptoms and Causes
What are the symptoms of non-alcoholic fatty liver disease?
People typically don’t experience symptoms until NAFLD progresses to NASH (non-alcoholic steatohepatitis). With NASH, you may begin to have symptoms of inflammation, such as pain and swelling in your upper right abdomen, where your liver is. But you may not notice symptoms until NASH has progressed to more severe liver damage. NAFLD merely lays the groundwork.
What causes a fatty liver in a non-drinker?
The answer to this is not yet entirely clear. But researchers suspect several factors at work, including:
- Metabolic syndrome. Non-alcoholic fatty liver disease seems to be linked to a group of related metabolic disorders involving high BMI, high blood lipid levels, high blood pressure and diabetes. These factors seem to influence each other and lead to collective changes in how your body metabolizes nutrients and stores fats.
- Diet and nutritional causes. Researchers have also found that a diet high in fructose may increase your risk of developing NAFLD. Fructose is one of the ingredients in common table sugar and is the dominant ingredient in high fructose corn syrup, a common sweetener. It’s highly linked to metabolic syndrome.
- Genetics. Certain genes may make you more likely to develop NAFLD. This may help explain why some people get it without any of the other common risk factors. It may also help explain why people of certain races seem to get it more often.
What are the possible complications of non-alcoholic fatty liver disease?
- Steatohepatitis. Up to 20% of people with non-alcoholic fatty liver disease may develop non-alcoholic steatohepatitis (NASH), a state of chronic inflammation of the liver. This can do progressive damage to your liver, eventually resulting in scarring of the tissues (cirrhosis).
- Pregnancy complications. NAFLD in pregnancy is associated with an increased risk of complications for both mother and baby. In particular, pregnant mothers are three-to-four times more likely to experience hypertensive complications such as preeclampsia.
Diagnosis and Tests
How is non-alcoholic fatty liver disease diagnosed?
Your healthcare provider may suspect NAFLD during a routine checkup if your blood panel shows high levels of certain liver enzymes or your liver appears enlarged on an imaging test. They may recommend further blood tests to rule out other causes of elevated liver enzymes. They may also want to try a more sensitive imaging test, such as a CT scan or MRI, to get a better look at your liver.
Another way of diagnosing non-alcoholic liver disease is to take a liver biopsy. That means collecting a sample of your liver tissue to test in the lab. Your healthcare provider collects the sample by inserting a needle into your liver. By analyzing the tissue, they can tell how much fat it has and whether there’s any evidence of steatohepatitis (NASH) or permanent scarring (cirrhosis).
Management and Treatment
Is non-alcoholic fatty liver disease reversible?
While there’s no medicine yet to reverse fatty liver disease, diet and lifestyle changes can help. Many people find that they can slow, stop and even reverse the fat accumulation in their liver by controlling metabolic factors such as weight, cholesterol (and other blood lipids), blood pressure and blood sugar. However, once NASH progresses to cirrhosis of the liver, the damage becomes more permanent.
How long does it take to reverse a fatty liver?
Healthcare providers recommend losing at least 3% to 5% of your body weight to begin to see results in your liver. (Current research suggests that even 1% weight loss may improve outcomes.) They also recommend that you aim to lose no more than 1 to 2 pounds per week. Rapid weight loss can make NAFLD worse. Take your time with a conservative diet and exercise program. Aim for 30 minutes of exercise a day.
How can I reduce my risk of developing non-alcoholic fatty liver disease?
Not all risk factors for NAFLD are avoidable, but you can work to control your weight, cholesterol, blood pressure and blood sugar with diet and medication as necessary. Watch your sugar and saturated fat intake, and make sure to see your healthcare provider for regular checkups.
Outlook / Prognosis
How long can you live with non-alcoholic fatty liver disease?
Non-alcoholic fatty liver disease isn’t life-threatening by itself. You may live the rest of your natural life without having any complications from it. It becomes more complicated for a small percentage of people when it turns to steatohepatitis (NASH), and especially when NASH progresses to cirrhosis. Research suggests that NAFLD overall may lower life expectancy by four years.
What kind of diet is recommended for non-alcoholic fatty liver disease?
Healthcare providers recommend a diet low in saturated fats and rich in unsaturated fats, (especially omega-3s), which help balance cholesterol, blood sugar and blood pressure. The Mediterranean diet is a good example. They also suggest avoiding sugar and keeping your glycemic index low. Replace sweets, processed foods and white bread products with whole fruits, vegetables and grains.
A note from Cleveland Clinic
Non-alcoholic fatty liver disease is increasingly common around the world, especially in Western developed countries where obesity, diabetes and other metabolic disorders have also been on the rise. While many factors might be at play, a common factor among these diseases is often an unhealthy diet and sedentary lifestyle. Fortunately, these things are in our power to change. By doing so, you can reduce the risk and even reverse the course of non-alcoholic fatty liver disease.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy