One of the most common phrases people hear during health checkups is "fatty liver." Many take it lightly, thinking, "I just need to lose some weight," or "I'll be fine if I cut back on drinking." But fatty liver is more than just fat accumulating in the liver. In some cases, it progresses to inflammation, then through liver fibrosis and cirrhosis, it can lead to liver cancer.
Bae Si-hyun, director of Eunpyeong St. Mary's Hospital and professor of gastroenterology, appeared on Seoul Economic Daily TV's "Now, Master Physician" at 9 p.m. Thursday. He stressed, "Fatty liver is no longer a disease to be taken lightly," adding, "It must be detected early, its causes corrected, and continuously managed."
◇ One in Three Adults Has Fatty Liver
Fatty liver patients are very common in Korea. "According to current Korean statistics, one in three people has fatty liver," Professor Bae explained. "In particular, 80% of fatty liver cases are not due to alcohol but are nonalcoholic fatty liver, that is, metabolic dysfunction-associated steatotic liver disease."
In the past, fatty liver was divided into alcoholic and nonalcoholic types, but recently the term "metabolic dysfunction-associated steatotic liver disease" is used. This is because even without drinking, metabolic disorders such as obesity, diabetes, hyperlipidemia, and lack of exercise can cause fat to accumulate in the liver.
"If the liver appears hazy on a liver ultrasound, it can be considered that fat already accounts for more than 5% of the liver," Professor Bae said. "Even if liver levels are normal, once fatty liver findings appear on an ultrasound, it should be considered a disease from that point on."
Thin people are not free from fatty liver either. Even with normal body weight, those with low muscle mass and high body fat, or who have "thin-obesity" with only a protruding belly, can develop fatty liver. "For men, a waist circumference of 90 cm, or about 36 inches or more, falls within the risk criteria for fatty liver," Professor Bae said. "You should not feel reassured just by looking at the number on the scale."
◇ Some Fatty Liver Progresses to Fibrosis, Raising Liver Cancer Risk
Fatty liver is dangerous because some cases progress to liver fibrosis. When repeated inflammation accumulates like scars on the liver, the liver hardens and can eventually lead to cirrhosis. Once the cirrhosis stage is reached, the risk of liver cancer rises significantly.
"Liver fibrosis stages 1 to 2 can return to normal through weight loss, exercise, and treatment of the underlying cause," Professor Bae explained. "But once it reaches stage 3 or higher, especially the cirrhosis stage, it may improve, but complete recovery to normal is difficult."
The causes of liver cancer are also changing. In the past, the main causes of liver cancer in Korea were hepatitis B and hepatitis C. However, as antiviral treatments have advanced, liver cancer caused by viral hepatitis is declining, while the risk of liver cancer from obesity, diabetes, and fatty liver is gradually growing.
"In the United States, metabolic dysfunction-associated steatotic liver disease has already emerged as a major cause of liver cancer and liver transplantation," Professor Bae projected. "Korea is also likely to head in the same direction as Westernized eating habits, late-night meals, and lack of exercise increase."
◇ Liver Levels Alone Are Not Enough; Ultrasound Must Be Examined Together
Fatty liver shows almost no particular signs. Many people think fatigue or discomfort in the upper right abdomen is due to the liver, but in reality, the causes are often sleep deprivation, stress, intestinal gas, or gallstones. "The liver is a silent organ," Professor Bae said. "Because there are no symptoms, health checkups and ultrasound examinations are important."
Even normal liver levels offer no reassurance. Even if AST and ALT levels are within the normal range, a trend of gradually rising compared to before may be a sign of progressing inflammation. "You should not judge liver health by liver levels alone," Professor Bae advised. "If you have obesity, diabetes, hyperlipidemia, or a family history, you should examine ultrasound and metabolism-related tests together."
◇ Losing 7% of Body Weight Improves Inflammation and Liver Levels
The key to treating fatty liver is weight loss. "If you lose 5% of your body weight, the fat in the liver decreases, and if you lose 7% or more, you can expect improvement in inflammation and liver levels," Professor Bae said. For example, for someone weighing 75 kg, losing at least 5 kg could be a target.
Recently, obesity treatments such as Wegovy and Mounjaro can also be used for fatty liver management. However, they are not immediately recommended for all fatty liver patients. "When liver levels are very high or there are abnormalities in fibrosis tests, and the condition cannot be controlled through lifestyle correction alone, the use of obesity treatments can be considered," Professor Bae said.
In terms of diet, particular caution should be paid to carbohydrate and fruit intake. "Rice and fruit are representative sources of carbohydrates," Professor Bae said. "Fruit is good food, but eating it to fullness can cause the remaining calories to accumulate in the liver." He recommended multigrain or brown rice over white rice and said it is better to reduce the amount compared to usual.
Exercise should combine aerobic and strength training. "Walking is good, but slowly walking while looking at your phone is not enough," Professor Bae said. "You need to do brisk walking that leaves you out of breath for at least 20 minutes to expect a fat-burning effect." When muscle mass increases, insulin resistance improves, which also helps with fatty liver management.
Coffee can help with liver health. "Several observational studies have found that bean coffee is associated with reducing liver inflammation, the progression of cirrhosis, and the occurrence of liver cancer," Professor Bae explained. "However, this refers to about two to three cups a day of bean coffee, not instant coffee mix."
On the other hand, he did not recommend oral albumin. "There is no evidence that oral albumin helps prevent liver inflammation, fibrosis, or liver cancer," Professor Bae said. "Rather, it is better to consume quality protein in meals, such as chicken breast, boiled pork, and pressed meat." Regarding milk thistle or Ursa, he said, "Some antioxidant effects have been reported, but the evidence is insufficient to consider them treatments that reduce liver fibrosis or the occurrence of liver cancer."
New drugs directly targeting fatty liver are also being developed. "There are drugs that have passed the FDA overseas, and they are expected to be introduced in Korea soon," Professor Bae said. "But more important than new drugs is managing weight and exercise, along with underlying conditions such as diabetes and hyperlipidemia."
◇ "Treatment Weapons" for Liver Cancer Increase
Meanwhile, regarding liver cancer, a malignant cancer, hospital director Bae Si-hyun said, "Treatment weapons have greatly increased." He added, "With the emergence of targeted therapies and immuno-oncology drugs on top of surgery, radiofrequency treatment, embolization, and radiation therapy, survival rates are rising even for advanced liver cancer." He explained that while surgery and embolization were the focus in the past, targeted therapies and immuno-oncology drugs are now opening a new paradigm in liver cancer treatment.
Multidisciplinary care is also important in liver cancer treatment. This involves internal medicine, surgery, radiology, and radiation oncology coming together to discuss the most appropriate treatment strategy for the patient. "At university hospitals, multidisciplinary care is mostly carried out," Professor Bae said. "It is good to decide the treatment direction together with medical staff at a hospital where the patient has been treated for a long time and one they trust."
Things You Must Never Do That Turn Fatty Liver into "Cancer" [Professor Bae Si-hyun, Department of Gastroenterology, Eunpyeong St. Mary's Hospital, Catholic University]
