The Medicine Cabinet: Ask the Harvard Experts
Q: I recently had an ultrasound that showed a fatty liver. What causes this? Is it dangerous?
A: The largest organ inside your body, your liver performs hundreds of vital functions. It converts food into fuel, processes cholesterol, clears harmful toxins from the blood, and makes proteins that help your blood clot, to name a few.
But an increasing number of people have a potentially dangerous accumulation of fat inside their livers. Doctors call it alcoholic fatty liver disease (NAFLD).
Prior to 1980, fatty liver disease was rarely diagnosed except in people who drank large amounts of alcohol. However, scientists discovered that excess body fat and diabetes can also cause fatty liver disease, even in people who drink very little.
As Americans have gotten fatter, so have their livers. Up to one-third of American adults have NAFLD. Nearly all people with severe obesity and half of people with diabetes have NAFLD. Some people with fatty livers have none of these risk factors, suggesting that genes and other factors play a role.
Also it can progress to cause a more serious liver condition, called nonalcoholic steatohepatitis (NASH).
In this condition, the fat within the liver causes the liver to become inflamed. In a subset of those with NASH scarring of the liver will develop. Severe scarring, known as cirrhosis, increases the risk of liver cancer and end-stage liver disease.
Treating fatty liver focuses on reducing or preventing further fatty buildup in the liver. Exercise and losing weight are the mainstays of treatment. Even a little exercise and shedding just a few pounds can reduce liver fat.
As for diet, the recommendation is similar to what doctors advise for preventing heart disease: Eat plenty of vegetables, fruits and whole grains, and modest amounts of lean protein, like fish and chicken. Avoid all sugary beverages and foods and limit refined carbohydrates.
(Howard LeWine, M.D. is an internist at Brigham and Women’s Hospital in Boston and assistant professor of medicine at Harvard Medical School. For additional consumer health information, please visit www.health.harvard.edu.)