Fatty Liver Disease as a Mirror of Metabolic Health

Scott Isaacs, MD, FACP, FACE
obese man holding side in pain

Non-alcoholic fatty liver disease, or NAFLD (pronounced na-ful-dee), is one of the most widespread and yet frequently underdiagnosed diseases in the United States (U.S.) and worldwide. Fatty liver disease is the number one cause of chronic liver disease in the U.S. and will soon surpass hepatitis C as the top cause of liver transplantation. Although NAFLD currently affects 75–100 million Americans, most people have never heard of it. Even among doctors, there is low awareness of this hidden epidemic.

Fatty liver disease is a direct result of our nation’s obesity epidemic. Approximately 20% of adults and 10% of children have NAFLD. But rates in those over 60 years of age are above 40%. People with type 2 diabetes and prediabetes are especially susceptible; as many as two out of three have a fatty liver.

NAFLD is similar to alcoholic liver disease but can happen in people who rarely or never drink. About 7% of people with fatty liver disease will progress to non-alcoholic steatohepatitis or NASH. When this happens, liver cells become injured and inflamed and form scarring known as fibrosis. Fibrosis leads to cirrhosis and increases the risk for liver cancer. People with diabetes have faster progression to NASH and liver scarring.

NAFLD is often a silent disease with few or no symptoms. NAFLD can cause fatigue which may be overlooked during a medical evaluation for tiredness. Other symptoms include nausea, yellowing of the eyes or discomfort in the upper right side of the abdomen.

"Fatty liver disease is a direct result of our nation's obesity epidemic. Approximately 20% of adults and 10% of children have NAFLD."

NAFLD is suspected by abnormal liver tests, primarily elevated liver enzymes (AST-aspartate aminotransferase, ALT-alanine aminotransferase), high ferritin or low platelets. Suspected NAFLD is then confirmed with an imaging study such as ultrasound, CT or MRI of the abdomen. Traditionally, the diagnosis of NASH has been made by liver biopsy, but this can be painful and expensive. New noninvasive tools have become another way to detect fibrosis in patients with fatty liver disease.

The management of NAFLD consists of treating the liver disease alongside the associated metabolic conditions such as obesity, diabetes and abnormal cholesterol. Weight loss is one of the most effective treatments for NAFLD while improving all of the metabolic conditions and decreasing the risk of heart disease. Although there are no approved drug therapies for NAFLD, some diabetes medications and vitamin E have been shown to be effective. Weight loss medications may also be beneficial for NAFLD, although there is very little research surrounding this topic. A type of weight loss surgery known as “metabolic surgery” is an effective treatment (such as gastric bypass in obese patients with BMI>35). New pharmaceutical agents that directly target NASH are in clinical trials. Liver transplantation is also a treatment for patients with end-stage liver disease.

Early detection allows people to make lifestyle changes, lose weight and be treated with medications that can reduce or reverse progression. Weight loss of 7% can reduce liver fat and inflammation in most patients.