Nonalcoholic fatty liver disease

Updated: 2024-04-04

Overview

Nonalcoholic fatty liver disease

Compared with a healthy liver (top), a fatty liver (bottom) appears bigger and discolored. Tissue samples show extra fat in nonalcoholic fatty liver disease, while inflammation and advanced scarring are seen in nonalcoholic steatohepatitis.

Nonalcoholic fatty liver disease, often called NAFLD, is a liver problem that affects people who drink little to no alcohol. In NAFLD, too much fat builds up in the liver. It is seen most often in people who are overweight or obese.

NAFLD is becoming more common, especially in Middle Eastern and Western nations as the number of people with obesity rises. It is the most common form of liver disease in the world. NAFLD ranges in severity from hepatic steatosis, called fatty liver, to a more severe form of disease called nonalcoholic steatohepatitis (NASH).

NASH causes the liver to swell and become damaged due to the fat deposits in the liver. NASH may get worse and may lead to serious liver scarring, called cirrhosis, and even liver cancer. This damage is like the damage caused by heavy alcohol use.

A move is currently underway to change the name nonalcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease (MASLD). Experts also have recommended changing the name nonalcoholic steatohepatitis to metabolic dysfunction-associated steatohepatitis (MASH).

Symptoms

The liver

The liver is the largest internal organ in the body. It's about the size of a football. It sits mainly in the upper right portion of the stomach area, above the stomach.

NAFLD often has no symptoms. When it does, they may include:

• Fatigue.
• Not feeling well, or malaise.
• Pain or discomfort in the upper right belly area.

Possible symptoms of NASH and cirrhosis, or severe scarring, include:

• Itchy skin.
• Abdominal swelling, also called ascites (uh-SY-teez).
• Shortness of breath.
• Swelling of the legs.
• Spider-like blood vessels just beneath the skin's surface.
• Enlarged spleen.
• Red palms.
• Yellowing of the skin and eyes, or jaundice.

When to see a doctor

Make an appointment with a member of your health care team if you have lasting symptoms that worry you.

Causes

Experts don't know exactly why fat builds up in some livers and not others. They also don't fully understand why some fatty livers turn into NASH.

NAFLD and NASH are both linked to the following:

• Genetics.
• Overweight or obesity.
• Insulin resistance, which happens when your cells don't take up sugar in response to the hormone insulin.
• Type 2 diabetes, sometimes called high blood sugar or hyperglycemia.
• High levels of fats, especially triglycerides, in the blood.

These combined health problems may contribute to a fatty liver. However, some people get NAFLD even if they do not have any risk factors.

Risk factors

Many diseases and health problems can increase your risk of NAFLD, including:

• Family history of fatty liver disease or obesity.
• Growth hormone deficiency, which means the body doesn't make enough hormones to grow.
• High cholesterol.
• High levels of triglycerides in the blood.
• Insulin resistance.
• Metabolic syndrome.
• Obesity, especially when fat is centered in the waist.
• Polycystic ovary syndrome.
• Obstructive sleep apnea.
• Type 2 diabetes.
• Underactive thyroid, also called hypothyroidism.
• Underactive pituitary gland, or hypopituitarism.

NASH is more likely in these groups:

• People older than 50.
• People with certain genetic risk factors.
• People with obesity.
• People with diabetes or high blood sugar.
• People with symptoms of metabolic syndrome, such as high blood pressure, high triglycerides and a large waist size.

It is hard to tell apart NAFLD from NASH without a clinical evaluation and testing.

Complications

Healthy liver vs. liver cirrhosis

A healthy liver, at left, shows no signs of scarring. In cirrhosis, at right, scar tissue replaces healthy liver tissue.

Esophageal varices

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 to the liver.

Liver cancer

Liver cancer begins in the liver cells. The most common type of liver cancer starts in cells called hepatocytes and is called hepatocellular carcinoma.

Severe liver scarring, or cirrhosis, is the main complication of NAFLD and NASH. Cirrhosis happens because of liver injury, such as the damage caused by inflammation in NASH. As the liver tries to stop inflammation, it creates areas of scarring, also called fibrosis. With ongoing inflammation, fibrosis spreads and takes up more liver tissue.

If nothing is done to stop the scarring, cirrhosis can lead to:

• Fluid buildup in the stomach area, called ascites.
• Swollen veins in your esophagus, or esophageal varices, which can rupture and bleed.
• Confusion, sleepiness and slurred speech, also called hepatic encephalopathy.
• Overactive spleen, or hypersplenism, which can cause too few blood platelets.
• Liver cancer.
• End-stage liver failure, which means the liver has stopped working.

Experts guess that about 24% of adults in the U.S. have NAFLD, and about 1.5% to 6.5% have NASH.

Prevention

To reduce your risk of NAFLD:

• Eat a healthy diet. Eat a healthy diet that's rich in fruits, vegetables, whole grains and healthy fats.
• Limit alcohol, simple sugars and portion sizes. Avoid sugary drinks like soda, sports drinks, juices and sweet tea. Drinking alcohol can damage your liver and should be avoided or minimized.
• Keep a healthy weight. If you are overweight or obese, work with your health care team to gradually lose weight. If you are a healthy weight, work to keep it by eating a healthy diet and exercising.
• Exercise. Be active most days of the week. Get an OK from your health care team first if you haven't been exercising regularly.

Diagnosis

Because NAFLD typically causes no symptoms, it is often found when tests done for other reasons point to a liver problem. For example, a blood test done during a yearly exam may show high levels of liver enzymes, which can lead to more testing and a NAFLD diagnosis.

Tests done to diagnosis NAFLD, rule out other diseases and see how bad liver damage is include:

Blood tests

• Complete blood count.
• Iron studies, which show how much iron is in your blood and other cells.
• Liver enzyme and liver function tests.
• Tests for chronic viral hepatitis (hepatitis A, hepatitis C and others).
• Celiac disease screening test.
• Fasting blood sugar.
• Hemoglobin A1C, which shows how stable your blood sugar is.
• Lipid profile, which measures blood fats, such as cholesterol and triglycerides.

Imaging procedures

Imaging tests used to diagnose NAFLD include:

• Abdominal ultrasound, which is often the first test used when liver disease is suspected.
• Magnetic resonance imaging (MRI) or computerized tomography (CT) scanning. These tests are better at finding mild liver fibrosis but can't tell NASH from NAFLD.
• Transient elastography, a newer type of ultrasound that measures the stiffness of your liver. Liver stiffness is a sign of fibrosis or scarring.
• Magnetic resonance elastography, which combines MRI imaging with sound waves to create a visual map, or elastogram, showing the stiffness of body tissues.

Liver biopsy

If other tests show signs of more-advanced liver disease or NASH, or if your test results are unclear, your doctor may suggest a liver biopsy. Liver biopsy is a procedure to remove a small piece of tissue from your liver. It is usually done using a needle through the abdominal wall. The tissue sample is looked at in a lab for signs of inflammation and scarring. Liver biopsy is the best way to diagnose NASH and clearly shows the amount of liver damage.

A liver biopsy can be uncomfortable, and it does have risks that your health care team will go over with you in detail. This procedure is done using a needle that is passed through the abdominal wall and into the liver.

Treatment

Treatment for NAFLD usually starts with weight loss. This can be done by eating a healthy diet, limiting portion sizes and exercise. Losing weight may improve other health problems that lead to NAFLD. Typically, losing 10% of your body weight or more is recommended. But losing even 3% to 5% of your starting weight can have benefits. Weight-loss surgery or medicines also may be helpful for certain people.

A new medicine is available to treat people who have NASH with moderate to severe liver scarring. Resmetirom (Rezdiffra) can help reduce the amount of fat that collects in the liver. This medicine is not recommended for people with cirrhosis. For those who have cirrhosis due to NASH, a liver transplant may be needed.

Lifestyle and home remedies

With help from your health care team, you can take steps to manage nonalcoholic fatty liver disease. You can:

• Lose weight. If you're overweight or obese, reduce the number of calories you eat each day and increase your physical activity to lose weight slowly. Eating fewer calories is key to losing weight and managing this disease. If you tried to lose weight in the past and couldn't, ask your health care team for help.
• Choose a healthy diet. Eat a healthy diet that's rich in fruits, vegetables and whole grains. Your health care team may suggest avoiding or limiting certain foods and drinks, such as white bread, red and processed meats, juices, and sweetened drinks. Keep track of all calories you take in.
• Exercise and be more active. Aim for at least 150 minutes of exercise a week. If you're trying to lose weight, you might find that more exercise is helpful. But if you don't already exercise regularly, get your health care team's OK first and start slowly.
• Manage your diabetes. Follow your health care team's advice to manage your diabetes. Take your medicines as told by your care team and watch your blood sugar closely.
• Lower your cholesterol and blood pressure. Improve your cholesterol levels and blood pressure if they are high. A healthy diet, exercise and medicines can help keep your cholesterol, triglycerides and blood pressure at healthy levels.
• Protect your liver. Avoid things that could harm your liver health. For example, don't drink alcohol. Follow the instructions on all medicines and nonprescription drugs. Check with your health care team before using any herbal supplements, as some can harm the liver.

Alternative medicine

No alternative medicine treatments are proved to cure nonalcoholic fatty liver disease. But researchers are studying whether some supplements or 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 canceling out the damage caused by inflammation. But more research is needed.

  Some evidence suggests vitamin E supplements may be helpful for people with NAFLD who don't have type 2 diabetes. Vitamin E supplements are not recommended for people with serious liver scarring or type 2 diabetes. Vitamin E has been linked with a slightly increased risk of heart disease and prostate cancer.

• Caffeinated coffee. Some studies suggest that coffee may benefit the liver by reducing the risk of liver diseases like NAFLD and lowering the chance of scarring. It's not yet clear how coffee may prevent liver damage. But certain compounds in coffee are thought to lower inflammation and slow scar tissue growth.

  If you already drink coffee, these results may make you feel better about your morning cup. But if you don't already drink coffee, this probably isn't a good reason to start. Discuss the possible benefits of coffee with your health care team.

Preparing for an appointment

See your family doctor or primary doctor first if you have symptoms that worry you. If your doctor suspects a liver problem, such as nonalcoholic fatty liver disease, you may be referred to a doctor who specializes in the liver, called a hepatologist.

Because appointments can be short, it's a good idea to be well prepared. Here are a few tips to help you get ready, and what to expect from your doctor.

What you can do

• Know what to do before your visit. When you make the appointment, ask if there's anything you need to do beforehand.
• Write down any symptoms you're having, including any that seem unrelated to the appointment.
• Make a list of all medications, vitamins or supplements you're taking.
• Take any relevant medical records, such as records of any tests you've had that relate to your current condition.
• Take a family member or friend along, if possible. Sometimes it can be hard to remember all the information you get during an appointment. Someone who comes with you may remember something that you missed or forgot.
• Write down questions to ask your health care team.

If you find out you have nonalcoholic fatty liver disease, some basic questions to ask include:

• Is the fat in my liver hurting my health?
• Will my fatty liver disease become serious?
• What are my treatment options?
• What can I do to keep my liver healthy?
• I have other health issues. How can I best manage them together?
• Should I see a specialist? Will my insurance cover it?
• Are there any brochures or other printed material that I can take with me? What websites do you recommend?
• Should I plan for a follow-up visit?

In addition to the questions that you've prepared to ask your care team, don't hesitate to ask questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

• Have you had any symptoms, such as yellowing of the eyes or skin and pain or swelling around your waist?
• If you had tests done at that time, what were the results?
• Do you drink alcohol?
• What medicines do you take, including over-the-counter medicines and supplements?
• Have you ever been told that you have hepatitis?
• Do other people in your family have liver disease?