The battle against hepatitis has largely been won, but rising fatty liver incidence has worrisome implications.

Mr. Lee and his wife have always been in fairly good health. Now well into their 60s, they still run a small tailor shop near Dongmen Market in Taipei. Both are slender and have never been overweight. 

To the surprise of Mrs. Lee, a routine health exam several years showed that she had fatty liver disease, a condition in which excess fat accumulates in the liver cells. Originally considered a benign condition, fatty liver is now increasingly seen as a possible precursor to serious hepatic illnesses, including steatohepatitis, liver fibrosis, cirrhosis, and even liver cancer.

“Non-alcoholic fatty liver disease (NAFLD) has become the most overwhelming liver disease in Asia,” wrote Taiwanese doctors Hsu Ching-sheng and Kao Jia-Horng in the Expert Review of Gastroenterology & Hepatology in 2017.

Fatty liver is often found in obese people and sometimes caused by heavy alcohol consumption. But Mr. Lee’s wife is neither obese nor a drinker. She thinks unhealthy food may have caused excess fat to build up in her liver. “Some Taiwanese food is very oily, especially restaurant food. It’s not healthy,” she says.

Restaurants in Taiwan commonly cook with soybean oil, which is high in polyunsaturated fat. A study published in the journal PLOS One in 2015 found that mice on a soybean oil diet developed fatty liver and ballooned hepatocytes as well as obesity, diabetes, and insulin resistance. The amount of soybean oil the mice ingested was similar to what a person consumes.

Taiwan’s Health Prevention Association (HPA) said in June that fatty liver is often linked to liver cancer cases in Taiwan. Liver cancer is the fourth most common cancer here, with about 11,000 cases a year. The HPA emphasized that obese people are three times as likely to have metabolic syndrome, a clustering of risk factors that raises the risk of heart disease and other health problems. Fatty liver is associated with metabolic syndrome.

Dr. Ho Mei-shang, an adjunct research fellow at Academia Sinica and specialist in infectious diseases and epidemic control, says that some people in Taiwan appear to be skinny, but have fat accumulated where it can do the most damage. “It’s hidden – it’s visceral obesity,” she says of the fat stored in the abdominal cavity padding the space between the internal organs.

A 2016 study published in Nutrition & Diabetes found that Asian women carried more abdominal and visceral fat as compared to Caucasian women with similar overall adiposity. “This may contribute to their elevated metabolic risk for obesity-related diseases,” the authors wrote.

The challenge to combating fatty liver is that it is largely asymptomatic in mild cases. Indeed, many people with mild cases may never develop other health complications. In addition. there are no drugs currently approved to treat it. Health specialists advocate lifestyle changes to reduce the incidence of fatty liver, such as a healthier diet and regular exercise.

To be sure, it is not easy to persuade people to make lifestyle changes, especially when a disease presents no symptoms. Fortunately, given Taiwan’s expertise in liver medicine, there is reason for hope.

After all, “Taiwan was the first country in the world to implement universal vaccination for hepatitis B in newborns,” Dr. Ho notes. That vaccination program was initiated in 1986, six years before the World Health Organization recommended that all countries do so.

Chronic hepatitis infection is a top risk factor for liver cancer. After the start of universal hepatitis B vaccination, liver cancer incidence fell steadily in Taiwan

Data from the Centers for Disease Control (CDC) shows that prior to mass vaccination, 90% of Taiwan’s population had been infected with hepatitis B before age 40, with 18-20% being carriers. Hepatitis B is spread when the bodily fluids of someone infected enters someone who is not infected. It can be sexually transmitted or spread by an infected mother to her child during birth.

In the 1970s, Taiwanese researchers discovered that mothers who were hepatitis B carriers had a 70% chance of passing the disease on to their child. That was one of the main drivers behind their efforts to persuade the government to vaccinate all newborns.

Despite the significant progress made fighting the disease, chronic hepatitis B remains a public health problem in Taiwan because some carriers were infected before universal vaccination. According to National Taiwan University’s Gastroenterology Division, Taiwan has roughly 2 million hepatitis B carriers, 20% of whom require medication.

Meanwhile, gastroenterologists urge Taiwan to do more to stymie fatty liver disease lest it become a public health crisis. “If we fail to cope with this growing health problem, NAFLD [non-alcoholic fatty liver disease] may gradually replace viral hepatitis as the major etiology of liver disease in Taiwan,” wrote doctors Hsu and Kao in the October 2012 edition of the Journal of the Formosan Medical Association.