Fatty Liver

What is fatty liver (steatotic liver disease)?

Steatotic liver disease (SLD), previously known as fatty liver, is a common chronic liver disease that occurs when excess fat is deposited in the liver of people who drink little or no alcohol. It is a spectrum encompassing patients with multiple metabolic risk factors and little alcohol intake (known as Metabolic-Dysfunction Associated Steatotic Liver Disease, or MASLD), to another spectrum of patients with excessive alcohol intake (known as alcohol-associated liver disease, or ALD).

It can range from ‘good fat’ or simple fat to ‘bad fat’ or metabolic dysfunction associated steatohepatitis (MASH). MASH can lead to liver cirrhosis and liver cancer.

What are the symptoms of MASLD?

MASLD usually does not cause symptoms. If symptoms are present, they may be non-specific type symptoms of tiredness, nausea and discomfort over the right upper abdomen. However, if MASLD progresses to cirrhosis, signs and symptoms of cirrhosis may appear, including:

• Itchy skin
• Easy bruising or bleeding
• Dark urine and pale stools
• Confusion, difficulty concentrating or memory issues (hepatic encephalopathy)
• Increased sensitivity to alcohol and medications
• Spider-like blood vessels on the skin (spider angiomas)
• Redness in the palms (palmar erythema)
• Enlarged spleen

How is MASLD prevented?

Adopting a healthy lifestyle can help reduce the risk of NAFLD and prevent its progression to more severe liver conditions.

• Maintain a healthy weight through a balanced diet and regular exercise
• Eat a diet rich in fruits, vegetables, whole grains and lean proteins
• Limit intake of processed foods, added sugars and saturated fats
• Engage in regular physical activity, such as brisk walking or strength training
• Manage conditions such as diabetes, high cholesterol and high blood pressure
• Reduce alcohol consumption or avoid it entirely
• Avoid unnecessary use of medications that may affect liver health
• Have regular health check-ups to monitor liver function and overall metabolic health

What causes MASLD?

Experts do not fully understand why fat accumulates in some livers but not others, or why some cases of MASLD progress to non-alcoholic steatohepatitis (NASH) while others do not.

What are the risk factors for MASLD? 

Risk factors for MASLD include:

• Diabetes
• Obesity (BMI>25 kg/m² in Asian people)
• Increased belly fat (central obesity) – waistline >90cm in Asian men or >80cm in Asian women
• Cholesterol problems
• Hypertension
• Metabolic syndrome
• Other associated conditions like obstructive sleep apnoea (OSA), polycystic ovary syndrome (PCOS), underactive thyroid (hypothyroidism), underactive pituitary (hypopituitary)

How is MASLD diagnosed?

MASLD is diagnosed by a combination of history, physical examination, blood tests and imaging studies of the liver.

• Liver function tests such as liver enzymes (ALT, AST) may be elevated
• Ultrasound, CT or MRI scans may show fatty liver
• Other blood tests may be needed to predict severity of disease or exclude other liver diseases
• Liver biopsy may be required to stage the disease

How is MASLD treated?

Treatment for MASLD may include:

Lifestyle modifications

• Weight loss
• Diet
• Exercise

Treatment of associated factors

• Control of diabetes, hypertension, obesity, cholesterol
• Medications

Medications

There is no specific medication approved solely for the treatment of MASLD or non-alcoholic steatohepatitis (MASH), but certain medications may help manage associated conditions and reduce liver damage. Treatment is usually tailored to individual needs and focuses on addressing underlying risk factors.

• Diabetes medications: Drugs such as metformin and GLP-1 receptor agonists (e.g., liraglutide, semaglutide) can improve insulin resistance, which may help reduce fat accumulation in the liver.
• Lipid-lowering medications: Statins (e.g., atorvastatin, rosuvastatin) are commonly used to manage high cholesterol and may reduce cardiovascular risk in people with fatty liver disease. They are considered safe for most patients with MASLD.
• Antihypertensive medications: If hypertension is present, ACE inhibitors, angiotensin receptor blockers (ARBs) or other blood pressure-lowering drugs may be prescribed to reduce the risk of liver and cardiovascular complications.
• Vitamin E: Some studies suggest that high-dose vitamin E may reduce liver inflammation in people with NASH who do not have diabetes, but it is not recommended for everyone due to potential long-term risks.

References

Wang, H., Sun, Y., Zhao, J., Wang, Y., Hu, D., Zhang, L., Liu, X., Zhang, Y., Huang, H., & Zhang, Y. (2024). Advances in the research of metabolic dysfunction-associated steatotic liver disease and its pathogenesis. International Journal of Molecular Medicine, 53(2), 1–11. https://www.spandidos-publications.com/10.3892/ijmm.2024.5412

Chalasani, N., Younossi, Z., Lavine, J. E., Diehl, A. M., Brunt, E. M., Cusi, K., Charlton, M., & Sanyal, A. J. (2018). The diagnosis and management of nonalcoholic fatty liver disease: Practice guidance from the American Association for the Study of Liver Diseases. Hepatology, 67(1), 328–357. https://pmc.ncbi.nlm.nih.gov/articles/PMC5643281/

Canadian Liver Foundation. (n.d.). Introduction to MASLD & MASH. https://fattyliver.ca/blog/f/introduction-to-masld-mash