Fatty Liver Disease Causes Explained

Fatty liver disease occurs when fat builds up in the liver. Nonalcoholic fatty liver disease is not related to alcohol use, while alcoholic fatty liver disease is. When fat accumulates on the body, it can start to deposit inside the organs, including the liver. The liver cells fill with large fat droplets and can become stressed or scarred. This damage can eventually lead to inflammation, which can progress to cirrhosis.

In its early stages, fatty liver disease generally has no symptoms. It may be referred to as a "silent disease" because people may not know that they have it. Symptoms may not appear until the disease is advanced. NAFLD is called nonalcoholic steatohepatitis (NASH) when liver damage occurs. Symptoms of NASH may include tiredness, weakness, yellowing of the eyes and skin, weight loss, itching, and spider-like blood vessels on the skin. Alcoholic fatty liver disease progresses to alcoholic hepatitis and alcoholic cirrhosis. Symptoms of these conditions may include abdominal pain, nausea and vomiting, loss of appetite, changes in weight, yellowing of the eyes and skin, increased thirst, weakness, sleep changes, confusion, fainting, and mood swings.

Common causes of fatty liver disease include obesity and alcohol consumption. There are numerous risk factors to consider. People who have prediabetes, type 2 diabetes, or obesity or those who drink heavily are most at risk. Other risk factors include high cholesterol, high triglycerides, high blood pressure, and metabolic disorder. People who are Hispanic and non-Hispanic whites have a higher risk than African Americans. Certain drugs, like cancer drugs and corticosteroids, toxins, and infections, can also increase the risk of developing fatty liver disease.

Diet, particularly high-fat, high-sugar foods, contribute to being overweight, which is one of the leading causes of fatty liver disease. According to Yale Medicine, most people with a BMI over 27 have fatty liver disease, meaning that the fall into the overweight, obese, or extreme obesity categories. Doctors may recommend that people who are overweight with fatty liver disease lose weight by making dietary changes. They may recommend limiting fat intake, replacing saturated and trans fats with unsaturated fats, avoiding foods with simple sugars (especially fructose), and eating more low-glycemic index foods like fruits, vegetables, and whole grains while avoiding high-glycemic index foods like white rice, white bread, and potatoes.

Early detection of fatty liver disease is essential to start making the necessary lifestyle changes to prevent the disease from progressing and damaging the liver. It is not easy to diagnose fatty liver because there are no symptoms. Your doctor may first suspect a problem if liver tests come back abnormal with general lab work. To make a diagnosis, your doctor will perform a physical exam and obtain a medical history. This history will include asking about your alcohol intake and any medications that you're taking. You may also need blood tests and imaging tests to check for fat or fibrosis in your liver. If the liver damage is significant, you may also need a biopsy.

Lifestyle changes are crucial for the management of fatty liver disease. A healthy diet with lots of vegetables, fruits, whole grains, and limited sugar and salt can be a good start. Exercise can help you lose weight and reduce the amount of fat in your liver. Your doctor may also suggest vaccinations for hepatitis A and B, flu, and pneumococcal disease. Getting hepatitis can cause even more damage to your liver, and people with liver disease are more likely to get infections, which makes the other vaccinations important. Talk to your doctor before taking any vitamins or supplements, as some can damage your liver.

There are no medical interventions for NAFLD and treatment of alcoholic fatty liver disease is generally supportive. If either kind of fatty liver disease leads to cirrhosis, doctors may use various medications, surgical procedures, or other interventions to manage it. In the case of liver failure, you may need a liver transplant.

The link between fatty liver and obesity is highly complex. Researchers do not know the exact cause of fatty liver. Still, some studies indicate that fatty acids, lipogenesis (the conversion of fatty acids into fats), insulin sensitivity, and inflammation may all play a role. This research also found that about 30 percent of people who are obese are "metabolically normal", meaning that the connection between the two is not absolute.

Alcohol has significant effects on the liver. It causes alcoholic fatty liver by altering the way that the liver processes various fats. Alcohol causes increased fatty acid uptake in the intestine, decreased fatty acid oxidation, increased production of fat, and decreased very-low-density lipoprotein (VLDL). The body absorbs more fatty acids, but the liver is less able to break down those fatty acids so they can be used effectively in the body. The fatty acid is instead turned into fat and stored. VLDL transports triglycerides (fats) from the liver to different body parts of the body. Less VLDL means less transport, so the triglycerides stay in the liver.

Research shows that exercise has significant benefits on NAFLD. Aerobic exercise and resistance training reduce fat in the liver by improving insulin resistance, fatty acid metabolism, mitochondrial function, and inflammation. (Research is not available on the effects of exercise on non-alcoholic fatty liver disease, which only occurs in people who drink heavily.)

Fatty liver disease can progress to cirrhosis and, if not managed, liver failure. Fatty liver can be reversed before it causes damage, but cirrhosis is not reversible. Doctors can cirrhosis in various ways. If it progresses to liver failure, the treatment is transplantation. To be considered for a transplant, people with alcoholic fatty liver disease will have to prove that they can stop drinking.

NAFLD is the most common cause of liver disease in children in the U.S., affecting between five and ten percent of children. This condition has become more common in the pediatric population in recent decades as childhood obesity has become more common. There are no medications to treat NAFLD in children; doctors typically recommend weight loss.

There are many drugs in development to treat fatty liver disease. They include molecular targets that act on various stages of fatty acid uptake and how the liver processes and stores fats, as well as gene therapy that acts on the vast number of genes connected to NAFLD. These studies are all still in the very early stages, so it will take some time before medication is available, assuming the trials go well.

Diet can help manage fatty liver disease and may even help prevent it. Generally, people with NAFLD should limit their intake of unhealthy fats and simple sugars. Fats are high in calories and can increase the risk of obesity. Avoid trans and saturated fats and replace them with unsaturated fats, like omega-3 fatty acids. Eat low-glycemic foods like fruits, vegetables, and whole grains to maintain healthy blood sugar levels. Avoid refined and processed sugars like fructose or sucrose. If you have NAFLD, you should also avoid drinking alcohol, as it can cause more liver damage.

There are many resources available for people with NAFLD, including online support groups, and the National Institute of Diabetes and Digestive and Kidney Diseases has information about clinical trials. For people with alcoholic fatty liver disease who may need support to stop drinking, there are many programs and support groups available.