Steatosis, commonly known as fatty liver, describes a condition where excess fat accumulates in liver cells. S3 steatosis represents the most severe grade, indicating that over 66% of liver cells contain fat. It is identified when a Controlled Attenuation Parameter (CAP) score, measured by a FibroScan, is between 290 and 400 dB/m, signifying substantial fatty change.
Common Causes and Underlying Conditions
S3 steatosis can stem from two primary categories: alcoholic fatty liver disease (AFLD) and non-alcoholic fatty liver disease (NAFLD), now often referred to as metabolic dysfunction-associated steatotic liver disease (MASLD). AFLD results from heavy alcohol consumption, where the liver’s process of breaking down alcohol generates harmful substances that damage liver cells and promote inflammation. Even short periods of heavy drinking can lead to alcoholic fatty liver disease.
NAFLD, or MASLD, is not linked to heavy alcohol use and is the most common form of liver disease globally, particularly in Western countries. Key risk factors for NAFLD include obesity (present in up to two-thirds of cases), type 2 diabetes, insulin resistance, metabolic syndrome, high cholesterol, and high triglycerides. These conditions lead to excessive fat accumulation in the liver because it becomes overwhelmed by high levels of fat from the bloodstream and diet, causing it to store fat within its cells.
Other less common causes of steatosis include certain medications like corticosteroids, amiodarone, tamoxifen, methotrexate, and valproic acid. Rapid weight loss, particularly after bariatric surgery or extreme dieting, can also paradoxically lead to fatty liver disease as fat is mobilized from adipose tissue and deposited in the liver.
Potential Health Implications of Severe Fatty Liver
S3 steatosis, if unaddressed, can progress through several serious stages of liver disease. Initially, simple steatosis, characterized by fat accumulation without significant inflammation, can advance.
The next stage is non-alcoholic steatohepatitis (NASH), now often called metabolic dysfunction-associated steatohepatitis (MASH), which involves fat accumulation along with inflammation and liver cell damage. This inflammation can lead to the formation of scar tissue in the liver, a process known as fibrosis. Fibrosis is graded from F0 (no fibrosis) to F4 (cirrhosis), with stages F2 and F3 indicating moderate to severe scarring.
As fibrosis progresses, it can lead to cirrhosis, a severe and often irreversible scarring of the liver where healthy tissue is replaced by extensive scar tissue, impairing liver function. Cirrhosis can take several years to develop, with progression rates varying based on factors like diabetes and body mass. Without treatment, cirrhosis can result in liver failure or increase the risk of hepatocellular carcinoma (HCC), a type of liver cancer.
Strategies for Managing and Improving S3 Steatosis
Managing and improving S3 steatosis primarily involves lifestyle modifications. Gradual and sustained weight loss is a key strategy, as even a 3-5% reduction in body weight can decrease liver fat, and a 7-10% reduction can improve liver inflammation and scarring. Exercise alone can prevent or reduce steatohepatitis, even without weight loss, and also helps maintain muscle mass during weight reduction.
Specific dietary changes are also beneficial. Adopting a balanced diet rich in fruits, vegetables, whole grains, nuts, legumes, and lean proteins like fish and poultry is recommended. The Mediterranean diet, with its emphasis on plant-based foods and healthy fats like olive oil, is often suggested. Conversely, limiting or avoiding processed foods, sugary snacks, refined carbohydrates such as white bread, red meat, and foods high in saturated fats is advised.
For individuals with alcoholic fatty liver disease, complete cessation of alcohol consumption is necessary to allow the liver to heal and potentially reverse damage. Even for NAFLD, avoiding alcohol is strongly recommended, as it can worsen symptoms and cause further liver damage.
Medical management involves working with a healthcare professional to address underlying conditions such as diabetes, high blood pressure, and high cholesterol. While there are currently no medications specifically approved to treat simple fatty liver disease, new treatments are emerging for NASH with moderate to severe liver scarring. However, lifestyle changes remain the primary and most effective approach for managing S3 steatosis.