An increasing number of obesity cases is driving an epidemic of a condition of excessive fat build-up in the liver. It is commonly called fatty liver disease (FLD) or hepatic steatosis.
A healthy liver contains a small amount of fat but when extra fat builds up in the liver and reaches 5% to 10% of your liver’s weight, it becomes a problem. Thus, understanding, diagnosing, and treating this progressive condition are becoming health priorities.
The liver is a reddish-brown, wedge-shaped, unequal two-lobed organ located just below the diaphragm, to the right of the stomach, and overlies the gallbladder. It is around 6 inches wide, and weighs approximately 3.3 pounds, making it one of the largest and heaviest organs in our body.
The liver is responsible for up to 500 separate functions, usually in combination with other body organs and systems. Various liver functions are carried out by the hepatocytes (liver cells). Given its size, the liver has multiple life-supporting functions such as:
Producing bile that helps with the digestion
Producing proteins necessary for growth
Storing iron needed by our red blood cells
Regulating glycogen storage and converting nutrients into energy
Producing substances that help blood clot for wound healing
Producing immune factors for immunity
Removing bacteria and toxins in our body for detoxification
Types of Fatty Liver Disease
Fatty liver disease has two types:
Non-alcoholic fatty liver disease (NAFLD)
Alcoholic liver disease
NAFLD is further subdivided into:
Simple fatty liver
Non-alcoholic steatohepatitis (NASH)
Don't let these terms get you confused. It is important to distinguish between simple fatty liver and NASH. Why? Because having a simple fatty liver does not cause liver-related sickness whereas having NASH means you have an inflammation or injury in your liver cells. NASH increases the risk of progression to more serious conditions like fibrosis (scarring) of the liver, liver cirrhosis, and liver cancer.
It is not yet clear why some people with NAFLD develop simple fatty liver and others develop NASH. Most people with NAFLD have simple fatty liver and not NASH. In the U.S., about 3% to 7% only of the US population has NASH.
Fatty liver occurs more often in adult males. It also affects about 10% of children in the U.S. NAFLD affects about 30% of people in Western countries and 10% of people in Asia. Fatty liver is more prevalent in Hispanic people than Caucasians, while Black people have the lowest susceptibility. Therefore, you have a greater chance of developing the fatty liver disease if you are Hispanic or Asian.
For people with NAFLD, there is about an 80% 10-year survival or recovery rate. However, the rate of progression of fibrosis is estimated to be 1 per 7 years in NASH and 1 per 14 years in NAFLD, with an increasing speed.
More than 90% of heavy drinkers develop fatty liver while about 25% develop the more severe alcoholic hepatitis.
Recently, the term Metabolic dysfunction-Associated Fatty Liver Disease (MAFLD) has been proposed to replace NAFLD. MAFLD is a more inclusive diagnostic name as it is based on the detection of fatty liver by biopsy, medical imaging, or blood tests but should be accompanied by either overweight/obesity, type 2 diabetes mellitus, or metabolic dysregulation. The new definition no longer excludes alcohol consumption or the coexistence of other liver diseases. Using this more inclusive definition, the global prevalence of MAFLD rises to 50.7%.
If we use the "old" NAFLD definition, 80% of obese people, 35% of whom progress to NASH, and up to 20% of normal-weight people have NAFLD despite no evidence of excessive alcohol consumption.
Signs, Symptoms, Diagnosis
Most individuals with fatty liver are asymptomatic. If there are symptoms, it may be occasional tiredness or pain in the upper right side of the abdomen. Thus, fatty liver disease is usually detected by accident when an abdominal ultrasound, CT scan, or MRI is requested for another reason or unrelated medical conditions and your doctor may be the first one to spot it. Because fatty liver disease often has no symptoms, people would only know it until the disease progresses to liver cirrhosis.
Elevated liver enzymes on a blood test for other conditions may raise a red flag. It is a sign of possible liver injury. To make a diagnosis, your doctor may order:
Ultrasound or CT scan to get a picture of the liver.
Liver biopsy to determine how far advanced the liver disease has progressed.
Elevated liver enzymes are found in 50% of patients with simple steatosis. A simple blood test may help to determine the magnitude of the disease by assessing the degree of liver fibrosis. Histological diagnosis by liver biopsy is the most accurate measure of fibrosis and liver fat progression as of 2018. It takes a liver biopsy to know if a person has simple fatty liver or NASH. But the infrequent complications and cost of a liver biopsy make this impractical for people with NAFLD.
Fatty liver is commonly associated with diabetes, hypertension, obesity, and dyslipidemia, but can also be due to any one of these:
Alcohol use - it is one of the causes of fatty liver due to the production of toxic metabolites like aldehydes during the metabolism of alcohol in the liver.
Abnormal metabolism - aside from the mentioned metabolic syndromes, abetalipoproteinemia, glycogen storage diseases, Weber–Christian disease, acute fatty liver of pregnancy, and lipodystrophy are considered to cause fatty liver.
Nutritional causes - obesity, insulin resistance, and malnutrition are the most common nutritional causes of fatty liver. Total parenteral nutrition, severe weight loss, refeeding syndrome, jejunoileal bypass, gastric bypass, jejunal diverticulosis with bacterial overgrowth may also cause fatty liver.
Drugs and toxins such as amiodarone, methotrexate, diltiazem, expired tetracycline, highly active antiretroviral therapy, glucocorticoids, tamoxifen, environmental hepatotoxins (e.g., phosphorus, mushroom poisoning)
Other causes such as celiac disease, inflammatory bowel disease, HIV, hepatitis C (especially genotype 3), and alpha 1-antitrypsin deficiency
Some people get the fatty liver disease without having any pre-existing conditions. But these risk factors make you more likely to develop it:
Being obese or overweight.
Having Type 2 diabetes or insulin resistance.
Having metabolic syndrome (insulin resistance, high blood pressure, high cholesterol, and high triglyceride levels).
Taking certain prescription medications, such as amiodarone, diltiazem, tamoxifen, or steroids.
Risks & Complications
Fatty liver disease doesn’t cause major problems for most people. However, it can turn into a more serious problem if it progresses into liver cirrhosis. Untreated liver cirrhosis eventually leads to liver failure or liver cancer.
NAFLD is intimately related to conditions like diabetes and obesity. It’s also linked to an increased risk of cardiovascular disease. The primary risks include alcohol, type 2 diabetes, and obesity. Other risk factors include certain medications such as glucocorticoids and hepatitis C.
Less than 10% of people with cirrhotic alcoholic FLD will develop hepatocellular carcinoma, the most common type of primary liver cancer in adults. But up to 45% of people with NASH without cirrhosis can develop hepatocellular carcinoma.
If you have been diagnosed with fatty liver disease, it is important to keep your liver as healthy as possible and avoid anything that can further damage your liver. Treatment of NAFLD is generally by dietary changes and exercise to bring about weight loss. Decreasing caloric intake by at least 30% or by approximately 750–1,000 kcal/day results in an improvement in hepatic steatosis. In more serious cases, medications that decrease insulin resistance, hyperlipidemia, and those that induce weight loss such as bariatric surgery as well as Vitamin E have been shown to improve or resolve liver function. For those who are severely affected, a liver transplant may be an option.
Here are some important things you should do:
Don’t drink too much alcohol. How much is too much remains debatable, but it’s probably best to avoid alcohol completely.
Make sure that none of your medications are toxic to the liver. Even acetaminophen may be harmful if you take too much for too long.
Get vaccinated to protect against hepatitis A and B.
Control other health conditions that might also affect your liver, and check with your doctor if you might have other underlying, treatable diseases contributing to your fatty liver.
Get regular screening tests for liver cancer if you already have cirrhosis.
Unfortunately, there are no FDA-approved medications for fatty liver disease. So far, the two best drug options affirmed by the American Association for the Study of Liver Diseases for biopsy-proven NASH are vitamin E (an antioxidant) and pioglitazone (used to treat diabetes). However, not everyone will benefit from these treatments, and there has been some concern about safety and side effects. If you have NASH, it’s best to ask your doctor whether these treatments are appropriate for you, as they are not for everyone.
Our body has an amazing ability to repair itself. So is our liver. Thus, fatty liver can be reversed. If you avoid alcohol, lose weight, and change your diet it is possible to reduce liver fat, inflammation, and reverse liver damage.
If you have questions regarding fatty liver disease, feel free to schedule a consultation. I will help and work with you and suggest changes that would help you. Who knows? One of the plans we offer might suit your needs. Or if you want to hear from me talk about Lifestyle Medicine, feel free to listen to our podcast or contact us.
Armand, Wynne. 2019. “Fatty Liver Disease: What It Is and What to Do About It” Harvard Health Blog. January 10, 2019.
Castera, Laurent, Mireen Friedrich-Rust, and Rohit Loomba. 2019. “Noninvasive Assessment of Liver Disease in Patients with Nonalcoholic Fatty Liver Disease.” Gastroenterology 156 (5): 1264-1281.e4.
Francque, Sven M., Giulio Marchesini, Achim Kautz, Martine Walmsley, Rebecca Dorner, Jeffrey V. Lazarus, Shira Zelber-Sagi, et al. 2021. “Non-Alcoholic Fatty Liver Disease: A Patient Guideline.” JHEP Reports: Innovation in Hepatology 3 (5): 100322.
Wikipedia Contributors. 2019a. “Liver.” Wikipedia. Wikimedia Foundation. July 6, 2019.
———. 2019b. “Fatty Liver Disease.” Wikipedia. Wikimedia Foundation. November 2, 2019. https://en.wikipedia.org/wiki/Fatty_liver_disease.