Nonalcoholic Steatohepatitis (NASH)

Medically Reviewed by Sabrina Felson, MD on April 09, 2023
6 min read

Metabolic dysfunction-associated steatohepatitis (MASH) is a disease in which a buildup of fat causes inflammation and damage to the liver. It used to be called nonalcoholic steatohepatitis (NASH). 

It’s a rare and more serious form of metabolic dysfunction-associated steatotic liver disease (MASLD), which used to be known as nonalcoholic fatty liver disease (NAFLD). There is no cure, but you can do things to keep it from getting worse and even repair the damage.

Doctors aren’t sure why some people collect extra fat in their livers. It also isn’t clear why some people with fatty livers go on to have steatohepatitis and others don’t. MASH is closely associated with obesity, but not everyone who gets it is overweight. 

Weight isn’t the only thing that puts you at risk. You’re also more likely to get MASH if you have type 2 diabetes, high cholesterol, or high triglycerides. It’s more common if you’re older, Hispanic, have high blood pressure or sleep apnea, or if you’re a woman who’s gone through menopause.

Researchers are looking into whether your genes, your diet, or the bacteria in your digestive system play a part in who gets MASH.

You can have steatohepatitis for years without knowing it. If you have any symptoms from liver inflammation at all, they’re usually minor – fatigue or mild pain in the upper right part of your abdomen. 

If MASH progresses, it can cause serious liver damage. Then you may have other symptoms like: 

  • Abdominal swelling 
  • Abnormal bleeding or bruising
  • Itching
  • Jaundice (yellow skin and eyeballs)
  • Serious weakness and fatigue
  • Spider veins
  • Unexplained weight loss

Because there aren’t many symptoms, steatohepatitis is often caught when you’re having tests done for something else. Your doctor will rule out other causes of liver inflammation, like alcohol use, viral hepatitis infection, or certain medications. The steps to getting a diagnosis include: 

Medical history. Your doctor will ask about things that put you at risk, like how much physical activity you get, whether you eat a lot of sugar, and if you have health conditions like type 2 diabetes. 

Physical exam. Your doctor will measure your height and weight to see if you’re overweight or obese. They may feel your abdomen to see if your liver and spleen are enlarged. 

Blood tests. They’ll test the amount of liver enzymes in your blood to find out how well your liver is working. You’ll likely also get your blood sugar and cholesterol levels checked. 

Imaging tests. Ultrasound, a CT scan, or an MRI scan can spot fat deposits or scar tissue in your liver. A kind of test called elastography can be done by ultrasound or MRI to measure how stiff your liver is. Your doctor might call this a fibroscan. 

Biopsy. The only way to know for sure if you have MASH, and how serious it is, is by surgically removing a small sample of liver tissue and looking at it under a microscope.

A diagnosis of steatohepatitis can be confusing and alarming. You may not have even known you were sick. Before your next appointment, it may help to write down some things to ask your doctor, such as:

  • How serious is my condition?
  • What treatment do you recommend?
  • Do I need to lose weight, and if so, what’s the best way for me to do that?
  • Should I see a liver specialist or a nutritionist?
  • What else can I do to keep my liver healthy?
  • How often should I have follow-up tests?
  • Should I be checked for diabetes?
  • Are there medications I should avoid?
  • What symptoms should I watch for that might mean it’s getting worse?
  • Do you know of any research studies I can join?
  • Where should I go for more information? 
  • Can I drink alcohol?

Steatohepatitis can’t be cured. But your liver is able to repair itself up to a point. If you take steps to stop the buildup of fat in your liver, you can keep MASH from getting worse and even reverse existing damage. 

In most cases, the main recommendation is that you lose weight. Dropping 7% to 10% of your body weight can get rid of stored fat in your liver and reduce inflammation and scarring. If diet and exercise aren’t enough, talk with your doctor about other options, like surgery. But weight loss needs to be gradual. If it’s too quick, that can also hurt your liver. 

One medication, resmetirom (Rezdiffra) has been approved to treat MASH. You use it in combination with lifestyle changes that will help you lose weight, like diet and exercise.

You should also get your blood sugar, blood pressure, and cholesterol levels into a healthy range. That may take medication or other treatments.

You may need to make some major lifestyle changes to manage steatohepatitis. If you can’t stop the buildup of fat in your liver, MASH can progress to more serious conditions with worse symptoms. 

You should also stay alert for signs of type 2 diabetes and cardiovascular disease because MASH puts you at higher risk for them. 

You’ll need to work closely with your doctor on a treatment plan and have your liver function and elasticity (how flexible it is) tested every so often to see whether the disease is improving. 

The liver damage caused by MASH can get worse. Constant inflammation causes scarring in your liver, called fibrosis. As areas of scar tissue take the place of healthy cells, your liver becomes stiff and can’t work as well as it should. 

Over time, the scarring can become widespread and impossible to repair – a condition called cirrhosis. Cirrhosis can eventually lead to liver failure, in which case you would need a liver transplant. It also puts you at higher risk for liver cancer. 

A healthy diet is key to managing steatohepatitis. Some experts recommend a Mediterranean-style diet, which emphasizes fruits and vegetables, whole grains, fish, and “good” fats. Whatever eating plan you choose, stick to these basics:

  • Limit the total amount of fat you eat, and make it unsaturated fat rather than saturated fat or trans fat. 
  • Choose food that doesn’t cause your blood sugar to spike. Your body processes things like white bread and white rice quickly. You digest food with protein and fiber slowly, which keeps your blood sugar levels more even. 
  • Stay away from sugary foods, especially soft drinks, juices, and baked goods that get their sweetness from fructose. If you eat more fructose than your body can use, your liver turns it into fat and stores it. 

There’s some evidence that vitamin E and caffeinated coffee may benefit your liver. Getting regular exercise can also lower the amount of fat in your liver and may help you lose weight. 

Let your family and friends know about your diagnosis. It isn’t easy to adopt a healthier lifestyle, and they can help reinforce your eating and exercise goals.

Look for a support group where you can share experiences and tips with people who have the disease. The American Liver Foundation has a Facebook group for people with MASH.

You may find it empowering to help scientists learn more about this disease and how to treat it. Clinicaltrials.gov is a database the U.S. National Library of Medicine operates where you can search for studies that you can participate in. 

In addition to eating well and exercising, you should take care to protect your liver from other things that can hurt it. 

  • Don’t drink. While MASH isn’t caused by alcohol, drinking only adds to the fat buildup in your liver. 
  • Be careful with vitamins and herbal supplements. Some can damage your liver. Clear all medications and supplements you take with your doctor.
  • Get vaccinated for hepatitis A and hepatitis B. Those infections are more likely to lead to liver failure when you already have liver damage from MASH. 

Most people who have steatohepatitis live just as long as people who don’t. You can help yourself by learning as much as you can about the disease and how to manage it, and following your doctor’s recommendations.