Non alcoholic fatty liver disease, often abbreviated as NAFLD, is a condition in which excess fat is stored in the liver. As its name suggests, NAFLD is not a consequence of heavy drinking, as is the case for alcohol-related liver disease, or simply ARLD. Rather, the term ‘non alcoholic fatty liver disease’ is used for individuals who consume very little alcohol, or for those who consume no alcohol at all. Generally speaking, NAFLD is more common in individuals who suffer from health conditions such as obesity, insulin resistance, type 2 diabetes, high levels of triglycerides or abnormal levels of cholesterol in the blood, and metabolic syndrome.
There are two main types of non alcoholic fatty liver disease – simple fatty liver and non alcoholic steatohepatitis. Simple fatty liver is a relatively harmless condition in which fat is present in the liver, but there is little to no inflammation or liver cell damage. Non alcoholic steatohepatitis, on the other hand, is a very serious form of the disease in which both inflammation of the liver and liver cell damage can occur. This latter condition, often abbreviated as NASH, can cause scarring of the liver and lead to cirrhosis as well as liver cancer. Approximately 20 percent of people with non alcoholic fatty liver disease have non alcoholic steatohepatitis.
More often than not, non alcoholic fatty liver disease causes no signs or symptoms. This is why NAFLD is often called a silent liver disease. People can live with excess fat in their liver for many years without developing liver damage or experiencing any symptoms. That said, individuals who progress from simple fatty liver to non alcoholic steatohepatitis are more likely to notice that something is wrong. The most common symptoms of NASH include feelings of weakness or severe fatigue, weight loss or long-lasting itching, spider-like blood vessels on the surface of the skin, and yellowing of the skin or the eyes.
Research into the exact cause of non alcoholic fatty liver disease is still ongoing. What experts do know, however, is that individuals who are overweight or obese, have insulin resistance, have abnormal levels of fats in the blood, have metabolic syndrome, or have type 2 diabetes are more likely to develop simple fatty liver and non alcoholic steatohepatitis. Less common causes of NAFLD include rapid weight loss, certain infections like hepatitis C, exposure to some toxins and a list of medicines, as well as disorders that cause the body to use or store fat improperly. Research suggests that certain genes may play a role in non alcoholic fatty liver disease as well.
Non alcoholic fatty liver disease is typically diagnosed by a blood test, but an imaging test or liver biopsy can also be used. In terms of treatment, doctors usually recommend weight loss to reduce the amount of fat in the liver. Replacing saturated fats and trans fats with monounsaturated fats and polyunsaturated fats is also advisable, in order to reduce the risk of heart disease. There are currently no approved medicines to treat simple fatty liver or non alcoholic steatohepatitis, but eating a healthy diet, limiting portion sizes, and maintaining a healthy weight through exercise can help prevent NAFLD all together.
Resources:
- https://www.niddk.nih.gov/health-information/liver-disease/nafld-nash/definition-facts
- https://www.hopkinsmedicine.org/health/conditions-and-diseases/nonalcoholic-fatty-liver-disease
- https://www.niddk.nih.gov/health-information/liver-disease/nafld-nash/eating-diet-nutrition