Medically reviewed by Kevin Tin, MD, Susan Kerrigan, MD and Marianne Madsen
The liver is one of the largest organs in your body. It plays a central role in all metabolic processes, including using bile produced by liver cells to break down and absorb fats before converting them to energy.
Liver disease occurs when the organ becomes inflamed and scar tissue, or fibrosis, starts to develop. Inflammation can be caused by many different factors such as viruses, metabolic processes and accumulation of fat in the liver, or, what we call steatosis. Steatosis is extremely common and most patients with steatosis may not develop inflammation. In those without inflammation and without a history of alcohol use, it is termed non-alcoholic fatty liver disease (NAFLD). In about 5% of patients, steatosis can induce inflammation in the liver and that can be further broken down as non-alcoholic steatohepatitis (NASH) or alcoholic steatohepatitis (ASH). If inflammation and fibrosis persists, then end-stage liver disease may develop, or what we call cirrhosis.
Nonalcoholic Fatty Liver Disease
NAFLD occurs when excess fat becomes stored in the liver. It is one of the most common liver diseases in the United States, with around 24% of adults having the disease. It is increasing in prevalence and is thought to soon be the leading cause of cirrhosis in the future. NAFLD patients tend to be made up of obese people or those that suffer from obesity-related conditions such as type 2 diabetes. Fatty liver disease can be a misnomer, as patients who are not overweight or obese can also develop NAFLD. This is usually due to other metabolic processes such as those patients with Type 1 diabetes or hyperlipidemia.
Symptoms and Causes of NAFLD
NAFLD is considered a silent disease. It has few or no symptoms, even in those patients who have developed cirrhosis. Several different risk factors can cause it. Apart from obese patients and those with type 2 diabetes, people with high or abnormal cholesterol levels or fat levels in their blood are likely to develop NAFLD.
There is much ongoing research for NAFLD and its causes, including looking at the relationship of fructose and high blood sugars in the development of NASH. Also, researchers have found a link between certain genes and NAFLD, which will make you more likely to develop the condition if you have them.
Suppose your doctor suspects you may have NAFLD. To make an accurate diagnosis, they will first take a full medical history to see if you suffer from any causes, such as obesity or type 2 diabetes. They may also ask about your diet, focusing on your sugar and alcohol intake. They may also give you a physical exam to check for signs such as insulin resistance, an enlarged liver, or signs of cirrhosis.
They will probably also do blood tests and imaging tests and maybe a liver biopsy to test for further signs of NAFLD, such as an enlarged liver and higher than normal levels of liver enzymes. Most commonly, patients would be found to have a mild elevation in their liver enzymes which would lead to further testing with an abdominal ultrasound which may show signs of a fatty liver.
While research and clinical trials are still ongoing, there are no FDA approved medications to treat NAFLD. The best way to treat NAFLD is to lose weight and increase your physical activity. Your doctor may recommend steadily losing up to 10% of your body weight to reduce liver inflammation and buildup of scar tissue. However, rapid weight loss should be avoided as this can make any liver disease worse.
Weight loss, eating a healthy diet, and maintaining a healthy weight are the best ways to prevent NAFLD and maintain a healthy liver. Some studies have shown taking daily Vitamin E 400 mg may play a protective role in treating fatty liver through its antioxidant effects.