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 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
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:
- • Abdominal swelling, also called ascites
- • Enlarged spleen
- • Itchy skin
- • Red palms
- • Shortness of breath
- • Spider-like blood vessels just beneath the skin's surface
- • Swelling of the legs
- • 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
- • High levels of fats, especially triglycerides, in the blood
- • Insulin resistance, which happens when your cells don't take up sugar in responses to the hormone insulin
- • Overweight or obesity
- • Type 2 diabetes, sometimes called high blood sugar or hyperglycemia
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
- • Obstructive sleep apnea
- • Polycystic ovary syndrome
- • Type 2 diabetes
- • Underactive pituitary gland, or hypopituitarism
- • Underactive thyroid, also called hypothyroidism
NASH is more likely in these groups:
- • People older than 50
- • People with certain genetic risk factors
- • 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
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:
- • Confusion, sleepiness and slurred speech, also called hepatic encephalopathy
- • End-stage liver failure, which means the liver has stopped working
- • Fluid buildup in the stomach area, called ascites
- • Liver cancer
- • Overactive spleen, or hypersplenism, which can cause too few blood platelets
- • Swollen veins in your esophagus, or esophageal varices,
which can rupture and bleed
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.
- • Exercise. Be active most days of the week. Get an OK from your health care team first if you haven’t been exercising regularly.
- • 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.
- • 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.
source: mayoclinic.org
