DEAR MAYO CLINIC: I recently read that fatty liver disease is becoming common in young children. What’s the cause of this condition? How is it diagnosed, and can it be reversed?

ANSWER: The number of children who have fatty liver disease is rising. Currently, about 10 percent of children in the U.S. have this disease. It is the most common cause of childhood chronic liver disease in this country. The increase is linked to the childhood obesity epidemic, as fatty liver disease is often caused by excessive weight gain. If it is caught and treated early, the disease typically can be reversed through lifestyle changes, including diet and exercise.

The liver is one of the largest organs in the body. About the size of a football, it is located on the right side of the abdomen, behind the lower ribs. Fatty liver disease (also called nonalcoholic fatty liver disease) occurs when fat builds up in the liver of people who drink little or no alcohol.
Typically the disease causes few, if any, symptoms. Many people with fatty liver disease have it for years and don’t know it. It is important for the disease to be diagnosed, however. If left unchecked, it could eventually lead to liver function problems, especially in children.

The most common cause of fatty liver disease in children is obesity. In children who are at a healthy body weight, fatty liver disease can also be the result of rare metabolic disorders, such as Wilson’s disease or cystic fibrosis, among others.

A doctor may suspect fatty liver disease if a blood test shows that a child’s level of liver enzymes is higher than normal, especially if the child is overweight. The disease also may be discovered through an imaging exam, such as an ultrasound. A diagnosis of fatty liver disease can be confirmed by microscopic examination of a small sample of tissue removed from the liver, a procedure known as a liver biopsy.

If caught while still in the early stages, fatty liver disease may be reversible. In children who are overweight, weight loss often is key to treating the disease. Weight loss usually is best accomplished with a combination of a healthy diet and regular physical activity.

In general, there are some strategies all families can use to help children reach and maintain a healthy weight. For example, make sure you have lots of healthy food choices available in your home. Buy plenty of fruits and vegetables. Cut down on convenience foods, such as cookies, crackers and prepared meals that are high in sugar and fat. Limit sweetened beverages, including fruit juices. These drinks are high in calories and low in nutritional value. They also can make a child feel too full to eat healthier foods.

Encourage your child to be physically active. This not only helps with weight loss, but also builds strong bones and muscles and helps a child sleep better at night. Keep in mind that activity does not have to be structured exercise to burn calories and improve fitness. Playing outdoors, jumping rope and going for hikes can all be good ways for a child to be active.

It is very important that children and teens avoid using supplements to help with weight loss or building muscle. Some of these supplements have recently been associated with acute liver failure and other dangerous health outcomes.

Don’t start a child on a specific weight-loss program before talking with his or her health care provider. It’s important that a weight-loss approach be tailored to a child’s individual situation and needs, including the child’s age and if he or she has any other health problems. — Samar Ibrahim, M.B., Ch.B., Pediatric Gastroenterology, Mayo Clinic, Rochester, Minn.