About one in four people in the United States has a condition in which some fat is found in their liver, according to the National Institutes of Health.
Many people assume problems with the liver are caused by too much drinking. In fact, this condition is not related to excessive alcohol consumption, which is why it has been called nonalcoholic fatty liver disease, which goes by the acronym NAFLD.
More recently, a global consensus of experts and patients proposed a more clear and non-stigmatizing term, metabolic dysfunction-associated steatotic liver disease, or MASLD. This name was selected because this condition is often associated with metabolic risk factors such as diabetes. As this name change adoption will take time, there will be a period where both names are used, including the acronym NAFLD/MASLD.
What’s most important for patients is that, while having excess fat in the liver may sound concerning, it is one of the most common causes of liver disease. In addition, not everyone with the condition needs treatment, and the condition is reversible with early diagnosis and treatment.
In this Q&A, Meena B. Bansal, MD, Professor of Medicine (Hepatology) at the Icahn School of Medicine at Mount Sinai, explains more about this disease—including possible treatments and when it could lead to complications. She is also Director of the Mount Sinai’s Center of Excellence for patients with this condition and Director of Translational Research, Division of Liver Diseases.
What is nonalcoholic fatty liver disease (NAFLD/MASLD)?
Many patients are told that they have fatty liver disease, either by their primary care doctor or by a radiologist who is doing an ultrasound. But not everyone with a little fat in their liver has NAFLD. People with NAFLD have fat in at least five percent of their hepatocytes, which are a type of liver cell. In some people, that fat stimulates inflammation and scarring of the liver.
Why is scarring important?
If the liver is injured, it responds by laying down scar, just as if you cut your hand you would develop a scar. If the injury is repetitive and continual, the liver continues to lay down scar. Scarring (also called fibrosis) accumulates over time and can cause cirrhosis. Fibrosis is the most important determinant of clinical outcomes in fatty liver disease. Some people develop a more advanced form of NAFLD, which is called nonalcoholic steatohepatitis (NASH), or in the new nomenclature (metabolic-dysfunction associated steatohepatitis (MASH).
How common is this condition? Who is most at risk?
The prevalence of NAFLD in the general population is about 25 percent. Fatty liver disease is very complex; there are a number of determinants, including genes, environment, diabetes, and obesity. If you have diabetes, are obese, have metabolic syndrome, or have HIV, you are at increased risk of developing NAFLD. You are also at increased risk if you have metabolic syndrome, which includes a number of conditions such as prediabetes, central adiposity (having a little excess weight around the waist), high triglycerides, low HDL (good cholesterol), or high blood pressure.
How can I get screened for this condition?
Your primary care doctor or any doctor can calculate a fib-4 score, which is based on four variables: age, platelet count, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). AST and ALT are liver enzymes. Your doctor probably already has these four pieces of information, so you shouldn’t need any additional blood test to get your fib-4 score. The FIB-4 score is very good—but not perfect—at ruling out significant liver disease. If your score is low, you can feel relatively confident that you don’t have cirrhosis or advanced liver disease. If the score is very high, you should see a liver expert (hepatologist) for further evaluation. And if you’re somewhere in between, you need some additional assessment.
What additional assessment would be needed?
If you have an intermediate Fib-4 score, you can get a Vibration Controlled Transient Elastography (VCTE) or Fibroscan. This test measures the stiffness of your liver. Many hepatologists have this scanner in their offices; Mount Sinai has a number of the scanners at various satellite locations. The machine sends a pressure wave through your liver and measures how fast the wave propagates. If your liver is soft, the wave goes slowly. If your liver is stiff because of scarring and inflammation, it moves faster.
What is cirrhosis?
Cirrhosis is when you have so much scarring it forms round nodules in your liver. It’s a natural wound healing response that has just been pushed to the limit.
Is NAFLD/MASLD treatable?
The good news is fatty liver is completely reversible. We can reverse it with weight loss, exercise, and lifestyle modifications. In addition, the scarring that NAFLD/MASLD causes is also reversible. The most important thing to know is how much fibrosis you have. Then you and your doctor can work on interventions and track your liver’s response to them. Even early cirrhosis is reversible. However, once you have had cirrhosis for a prolonged period, you may reach the point where it is not reversible. Our goal is to help you before you get to that point.
How can Mount Sinai help?
When someone is referred to us for fatty liver disease (NAFLD/MASLD), we first confirm the diagnosis. It’s very important to make sure there are no other ongoing liver diseases that would require a different treatment course. Next, we assess how much scarring your liver has. Once we’ve established that, we develop a treatment plan.
What does a treatment plan look like?
The best treatment for fatty liver disease is exercise and weight loss. Studies show that losing 10 percent of your body weight causes fibrosis regression or a decrease in scarring. We recommend a Mediterranean diet. This approach emphasizes eating plant-based foods and healthy fats. In addition, we recommend black coffee, which is protective for the liver—you can have a couple of cups a day. If you have significant scarring in the liver, we may want to see if you might be eligible for one of our many clinical trials. We usually have at least ten active clinical trials for patients with various levels of fatty liver disease or fibrosis. We will also monitor how your liver is doing over time. Is the scar accumulating at a rapid rate or is it mostly stabilized? Each patient is different and it is important to know your trajectory.