As we all know that obesity occurs due to excess fatty tissue in the body. But what happens if excess fat gets accumulated in the liver? It leads to a liver condition known as fatty liver disease. As obesity is a global epidemic, the occurrence of fatty liver disease is also increasing in an overwhelming rate. More specifically, obesity is known to be associated with an increased risk of nonalcoholic fatty liver disease (NAFLD).
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About fatty liver disease +
Liver is the largest organ in the body. It performs diverse functions like drug metabolism, and detoxification of chemicals. It is also involved in purification of blood from digestive tract and production of proteins that are involved in blood clotting.
A healthy liver contains little or no fat. But a fatty liver disease is a condition in which fats get accumulated in the liver. There are two types of fatty liver disease.
- Non-alcoholic fatty liver disease (NAFLD), as the name implies, is the liver condition seen in people who do not consume alcohol or take it in less amounts.
- Alcoholic fatty liver disease (ALD) occurs in people who consume excess amounts of alcohol.
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How obesity causes fatty liver disease? +
Both alcohol and obesity seem to have similar impact on the liver. Maintaining a normal BMI is as important as it is to avoid alcohol to prevent liver diseases. Obesity increases the risk of NAFLD but having comorbid conditions like high blood pressure and diabetes mellitus can further increase the risk.
Insulin resistance, which is closely associated with obesity, is found to be the chief cause of nonalcoholic fatty liver disease (NAFLD). More specifically people with abdominal obesity, who are more prone to develop insulin resistance early, are more likely to have NAFDL. The following are the different stages of liver damage that can occur in NAFDL, and all the stages are found to be associated with insulin resistance that is found in majority of obese individuals.
Stages of non-alcoholic fatty liver disease (NAFDL)
- The initial stage of fatty liver disease occurs when the liver starts to store excess amount of fat in its own cells as a result of insulin resistance. It is characterized by increase in triglycerides in the liver (Intrahepatic triglyceride content (IHTC). The initial stage of NAFLD is known as steatosis.
- If the fat is accumulated in the liver for prolonged duration may cause inflammation (hepatitis) or damage the liver cells (necrosis) leading to a more severe condition called non-alcoholic steatohepatitis (NASH).
- If the damage continues, NASH can eventually cause scarring of the liver- a condition called as fibrosis. The permanent scaring of the liver called cirrhosis, which is the last stage of NAFLD. Cirrhosis may lead to liver failure or liver cancer.
Obesity increases the risk of NAFLD but having comorbid conditions like high blood pressure can further increase the risk.
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A closer correlation of BMI with Liver diseases +
Obesity is found to be a major risk factor for a liver condition called non-alcoholic fatty liver disease. As a person’s body mass index increases, the rate at which NAFLD occurs also increases. Drastic increase in the prevalence rates of liver changes are observed in class I (BMI 30.0 - 34.9 kg/m2) and Class II (BMI 34.9 – 39.9 kg/m2) obesity. The prevalence rates of steatosis and steatohepatitis are as high as 65%, and 20% respectively in persons with class I and class II obesity; and 85% and 40% respectively in patients with severe obesity (BMI ≥40 kg/m2)1.
The relationship between BMI and NAFLD in people may vary depending on the racial or ethnic background. Along with BMI, higher waist circumference (WC) in obese people also acts as the clinical parameter associated with higher risk for NAFLD.
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Diagnosis of NAFLD +
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Blood tests: Mild elevation in the levels of the liver enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the blood may indicate NAFLD. So, a blood test that measures liver enzymes can help in diagnosis. But the presence of any other conditions that may raise the liver enzymes should be ruled out.
- Imaging techniques: Imaging techniques like ultrasound, fibroscan, Magnetic resonance imaging (MRI) or Computerized tomography (CT) detect liver fat and liver hardness (fibrosis) with reasonable accuracy.
- Biopsy: Only a liver biopsy can confirm the diagnosis for the presence of nonalcoholic fatty liver disease (NAFLD). It can also help to identify the stage of the NAFLD.
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Steps to avoid NAFLD +
Both alcohol and obesity seem to have similar impact on the liver. Maintaining a normal BMI is as important as it is to avoid alcohol to prevent liver diseases.
Non-alcoholic fatty liver disease in its initial stages does not cause any harm to the liver. But prolonged fat accumulation may result in more serious conditions. There are a few lifestyle measures which can help to curb progression of fatty liver disease:
Diet: It is important to following a healthy and well-balanced diet. Obese people should be advised to include more amounts of fruits and vegetables and food with low glycemic index and to avoid processed and sugary foods.
Weight loss measures: Weight loss and steps towards correcting the elevated cholesterol and triglyceride levels are be beneficial in non-alcoholic fatty liver disease. Decrease in weight can also help to reverse the condition, depending on the stage of the condition. So, one should have a regular check on their weight and follow a weight reduction program, if necessary, to keep liver disease away.
What Happen with weight loss in Fatty Liver?
References
1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575093/
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