The Most Common Liver Disease You've Never Heard of
Nonalcoholic Fatty Liver Disease, the most prevalent liver disease in the world, affects almost two billion people
It's one of our most important organs. It's the size of a football and weighs as much as a three pound mini-watermelon. Sitting in the upper right side of the body, it serves myriad functions, including storing nutrients and iron, producing bile, removing waste products from the blood and filtering and processing chemicals found in food, alcohol and medications.
It's your liver.
And if you think, "Well, I'm not a heavy drinker, so I don't have to worry about liver disease," you could be wrong. Very wrong.
"We are seeing a large group of baby boomer patients, many of whom have been harboring silent liver disease for decades."
According to the American Liver Foundation, about 25% of U.S. adults have Nonalcoholic Fatty Liver Disease (NAFLD), the most prevalent liver disease in the world, affecting almost two billion people.
NAFLD is the umbrella term for the disorder in which excess fat accumulates in the liver of people who are not heavy alcohol users. When more than 5% to 10% of the liver's weight is fat, it's considered a fatty liver (steatosis), which is a relatively benign condition. A more serious subset is called nonalcoholic steatohepatitis (NASH), which causes liver inflammation, damage to liver cells and fibrosis (scarring). This variant of the disorder is seen in about 20% of cases of nonalcoholic fatty liver disease.
A Silent Disease
Dr. Scott L. Friedman, chief of the division of liver diseases and a professor at the Icahn School of Medicine at Mount Sinai in New York City, says, "We are seeing a large group of baby boomer patients, many of whom have been harboring silent liver disease for decades."
They are frequently in their fifties when the disease begins to progress, he noted. "NASH is often discovered through routine blood tests when certain liver enzymes are found to be elevated, or incidentally through abdominal ultrasound procedures that are done for unrelated reasons," said Friedman.
"I believe the next five years will completely redefine not only treatment of nonalcoholic fatty liver disease, but also the diagnostic process."
With enough damage, NASH can lead to cirrhosis, in which hard scar tissue replaces healthy liver tissue and interferes with the organ's ability to work effectively.
The presence of scarring, more than the high fat content itself, is primarily responsible for the deleterious effect on the liver.
The National Institutes of Health anticipates that by 2030, NASH, along with cirrhosis caused by alcoholic liver disease, will be the most common reason for liver transplants. NAFLD is seen most frequently in people with metabolic syndrome, which is characterized by Type 2 diabetes or pre-diabetes (insulin resistance), obesity, especially with excess belly fat, high blood pressure and elevated cholesterol and triglyceride levels. The highest prevalence is in the Latino population.
Fatty liver disease is also independently associated with cardiovascular disease, chronic kidney disease and type 2 diabetes mellitus, even if the other elements of metabolic syndrome are not present.
Although NAFLD is usually associated with obesity, 10% to 20% of people with the disease have what is referred to as lean NAFLD, or lean NASH, with a normal BMI (body mass index). Unfortunately, even these normal-weight individuals can suffer liver damage.
Diagnosis and Treatment
While people with fatty liver disease often feel well until the disorder is more advanced, symptoms may include abdominal pain or sensation of fullness in upper right side of the belly, nausea, loss of appetite, unexplained weight loss, swollen legs, yellowing of the skin and eyes (jaundice) and extreme tiredness or weakness.
Once liver disease is suspected, advanced imaging techniques and other tests are used to diagnose nonalcoholic fatty liver disease. These may include:
- Magnetic Resonance Elastography, which helps create a map of the liver to reveal areas becoming stiff and showing increased fat
- Computerized tomography (CT scan) and ultrasound, which shows excess liver fat or liver enlargement
- Transient elastography (Fibroscan), a relatively new diagnostic technique similar to ultrasound
- Liver biopsy
Living With Fatty Liver Disease
If you are diagnosed with nonalcoholic fatty liver disease, lifestyle modifications — such as healthy eating with low amounts of dietary fat, exercise, weight loss, limiting or eliminating alcohol, and managing diabetes, high blood pressure and other medical conditions — are the cornerstone of treatment. As of now, there are no Food and Drug Administration (FDA) approved medications for these conditions.
Other recommendations include:
- Stay up to date with annual check-ups and recommended vaccinations including Hepatitis A and B. Preventing other liver diseases will help lessen the impact of NAFLD or NASH, as will early diagnosis. In a major change from 2013 guidelines, when only adults born from 1945-1965 (and those with risk factors) were told to be screened for Hepatitis C, the U.S. Preventive Services Task Force in March 2020 issued updated recommendations urging routine antibody testing for all adults ages 18-79. Hepatitis C antiviral medications today are highly effective, with many fewer side effects than previously.
- If you have been told you snore loudly or have other possible symptoms of sleep apnea, speak with your physician. Sleep apnea is an independent consequence of metabolic syndrome, particularly of obesity, and may worsen liver disease because of decreased oxygen levels in the body, explains Friedman.
- If there are no medical contraindications, have several cups of caffeinated coffee per day. Numerous research studies have shown that coffee has a protective effect on the liver, leading to some improvement in fatty liver and scarring and a reduction in cirrhosis and the risk of liver cancer. Sodas, chocolate and other substances containing caffeine do not appear to have the same beneficial effects.
- Be aware of possible side effects of medications you are prescribed. Some drugs, such as methotrexate, (a drug used to treat cancer), tamoxifen and prednisone, can have adverse effects on the liver which should be carefully monitored.
- Watch out for certain supplements and herbs. "Patients with NAFLD or any type of liver disease must be extremely wary of dietary supplements and herbal remedies, unless explicitly recommended by your doctor, because they are not FDA regulated and can be dangerous," says Friedman. He adds: "We have countless examples of patients who have suffered life threatening liver disease from things such as protein shakes." Milk thistle (silymarin), green tea extract and other supposed liver "strengtheners" or "detoxification supplements" should be avoided. Vitamin E has been the subject of numerous trials and may be worth discussing with your health care provider.
On a more positive note, Friedman says, "Fatty liver disease is one of the hottest areas in drug development right now. There are dozens of pharmaceuticals in Phase 1 and Phase 2 clinical trials, and numerous companies are working on targeted therapeutics to stop fat accumulation, inflammation, scarring or all of the above. The overriding goal is to reduce fibrosis so the liver can continue to do what it needs to do."
Another goal, he adds, is to develop more refined methods of diagnostic imaging and biochemical testing that are less invasive than liver biopsies.
"I believe the next five years will completely redefine not only treatment of nonalcoholic fatty liver disease but also the diagnostic process," says Friedman. "This is an exciting and vibrant time for the field of liver research."