Nonalcoholic fatty liver disease, or NAFLD, is a liver condition affecting individuals who consume minimal to no alcohol. In NAFLD, an excess accumulation of fat occurs in the liver, predominantly observed in those who are overweight or obese.
The prevalence of NAFLD is on the rise globally, particularly in Middle Eastern and Western nations where obesity rates are escalating. As the most prevalent form of chronic liver disease, NAFLD impacts approximately 25% of the world’s population, with around 100 million people in the United States alone diagnosed with the condition.
For some individuals with NAFLD, the condition progresses to nonalcoholic steatohepatitis, commonly known as NASH. NASH represents a severe form of fatty liver disease, resulting in liver swelling and damage due to the accumulation of fat deposits. Left untreated, NASH may advance, leading to substantial liver scarring known as cirrhosis and, in extreme cases, the development of liver cancer. The extent of damage is akin to that caused by excessive alcohol consumption.
Presently, there is an ongoing effort to rename nonalcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease (MASLD). Similarly, experts are advocating for the reclassification of nonalcoholic steatohepatitis to metabolic dysfunction-associated steatohepatitis (MASH).
Symptoms
NAFLD typically manifests without noticeable symptoms. However, when symptoms do occur, they might encompass:
- Fatigue.
- General feelings of unwellness or malaise.
- Pain or discomfort in the upper right abdominal area.
In cases of NASH and cirrhosis (severe liver scarring), potential symptoms include:
- Itchy skin.
- Abdominal swelling, also referred to as ascites.
- Shortness of breath.
- Swelling of the legs.
- Spider-like blood vessels just beneath the skin’s surface.
- Enlarged spleen.
- Red palms.
- Yellowing of the skin and eyes, known as jaundice.
Causes
The precise reasons for the accumulation of fat in certain livers and the progression of some fatty livers to NASH remain unclear to experts. Additionally, the full understanding of why individuals develop NAFLD and NASH is still incomplete.
Both NAFLD and NASH are associated with the following factors:
- Genetics.
- Overweight or obesity.
- Insulin resistance, a condition where cells fail to uptake sugar in response to insulin.
- Type 2 diabetes, also known as high blood sugar or hyperglycemia.
- Elevated levels of fats, particularly triglycerides, in the bloodstream.
The interplay of these health conditions may contribute to the development of a fatty liver. It is worth noting that some individuals may develop NAFLD even in the absence of these identified risk factors.
Risk factors
Various diseases and health conditions can heighten the risk of developing NAFLD, including:
- Family history of fatty liver disease or obesity.
- Growth hormone deficiency, indicating insufficient hormone production for growth.
- High cholesterol levels.
- Elevated levels of triglycerides in the bloodstream.
- Insulin resistance.
- Metabolic syndrome.
- Obesity, particularly when fat is concentrated around the waist.
- Polycystic ovary syndrome.
- Obstructive sleep apnea.
- Type 2 diabetes.
- Underactive thyroid, also known as hypothyroidism.
- Underactive pituitary gland, or hypopituitarism.
NASH is more prevalent in specific groups, including:
- Individuals over the age of 50.
- Those with certain genetic predispositions.
- People dealing with obesity.
- Individuals with diabetes or high blood sugar.
- Those displaying symptoms of metabolic syndrome, such as high blood pressure, elevated triglyceride levels, and an increased waist size.
Distinguishing between NAFLD and NASH without a clinical evaluation and testing can be challenging.
Cirrhosis, characterized by severe liver scarring, stands as the primary complication arising from NAFLD and NASH. The development of cirrhosis is attributed to liver injury, particularly the damage inflicted by inflammation in NASH. In an attempt to counteract inflammation, the liver generates areas of scarring, also known as fibrosis. As inflammation persists, fibrosis expands, occupying more liver tissue.
Failure to intervene and halt the progression of scarring can lead to the following consequences of cirrhosis:
- Accumulation of fluid in the abdominal area, referred to as ascites.
- Swollen veins in the esophagus, known as esophageal varices, which may rupture and cause bleeding.
- Cognitive impairment, drowsiness, and slurred speech, collectively termed hepatic encephalopathy.
- Hyperactive spleen, or hypersplenism, resulting in a shortage of blood platelets.
- Increased risk of liver cancer.
- End-stage liver failure, indicating the complete cessation of liver function.
Approximately 24% of adults in the United States are estimated to have NAFLD, with approximately 1.5% to 6.5% progressing to NASH, as per expert estimations.
Prevention
To mitigate the risk of NAFLD, consider the following lifestyle measures:
Adopt a nutritious diet: Embrace a diet abundant in fruits, vegetables, whole grains, and healthy fats to promote overall well-being.
Restrict alcohol, simple sugars, and portion sizes: Minimize or eliminate alcohol consumption and steer clear of sugary beverages like soda, sports drinks, juices, and sweet tea. Moderating portion sizes is also advisable.
Maintain a healthy weight: Collaborate with your healthcare team to achieve gradual weight loss if you are overweight or obese. If you are at a healthy weight, sustain it through a balanced diet and regular exercise.
Engage in regular exercise: Incorporate physical activity into most days of the week. Consult your healthcare team before initiating a new exercise routine, especially if you haven’t been active regularly.
