What with the obesity epidemic overtaking almost every other health condition, it will soon overtake alcohol as the number one cause of liver disease.
Obesity risks are associated with visceral fat (central abdominal obesity) rather than subcutaneous fat. It is believed that visceral fat releases free fatty acids, which are accumulated in the liver. Obesity, thus, increases the risk of non-alcoholic fatty liver disease (NAFLD).
Your liver enzymes rise and the liver gets infiltrated with fat deposits. Further, if ignored, there can be accompanying inflammation and still further on over the years, cirrhosis can develop in which there is progressive scarring of the liver parenchyma.
Metabolic liver disease (not associated with alcohol) is the most common liver disease in western countries.
Obesity, fatty liver disease, and liver cirrhosis
The term, non-alcoholic fatty liver disease (NAFLD), is broadly used to describe the effects of obesity on the liver.
NAFLD is one of the most common liver diseases in people with excess weight who do not drink alcohol or drink less than two pegs a day.
It is an umbrella term used to describe three liver diseases ranging from:
- Fatty liver. The most common form of fatty liver is called steatosis, which is the accumulation of fat in the liver. When fat accounts for more than 5 to 10 percent of your liver’s weight, you are said to have fatty liver. This condition is reversible by following the right diet and modifying your lifestyle. It is the most common non-serious form of liver disease.
- NASH. Non-alcoholic steatohepatitis is fat deposit in the liver accompanied by inflammation and damage of the liver cells. This can last for years and some amount of scarring may also be present. This is a serious condition and should not be ignored.
- Liver cirrhosis. Ignored steatohepatitis can lead to cirrhosis. Cirrhosis of the liver is an irreversible progressive fibrosis of the liver caused by chronic inflammation. This is a serious liver condition in which the liver does not function properly. The liver is substantially damaged because the liver cells are gradually replaced by scar tissue.
These are all various progressive stages of NAFLD and are believed to be due to insulin resistance, which is a common companion of obesity. BMI and liver damage have a direct correlation, which means that more the BMI more will be the liver damage.
Therefore, if not corrected, obesity can be the cause of you developing non-alcoholic cirrhosis.
NAFLD, as mentioned above, is the most common liver disease, affecting 10 to 24% of the global population and 25% of the U.S. population.
Obesity and liver enzymes chemistry
In a fatty liver, you will find that the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are elevated. But, to confirm the diagnosis, an ultrasound is done. Fat deposits will be seen as white patches.
In NASH, the most common abnormal laboratory test results are elevated (ALT) and (AST), usually one to four times the upper limits of normal. Ultrasonography or computed tomography also help but liver biopsy is regarded as the gold standard and is the only reliable method for differentiating NASH from a simple fatty liver.
In cirrhosis, serum bilirubin may be slightly increased and rises very high when the cirrhosis is advanced. ALT and AST are raised and the ultrasound shows nodules on the liver surface. Liver biopsy is the ultimate test to confirm cirrhosis of the liver.
Obesity and hepatocellular carcinoma (HCC)
Obesity very strongly increases your risk of liver cancer especially hepatocellular carcinoma. People with high BMI are at the highest risk of this form of liver cancer.
A study conducted shows that morbidly obese individuals with BMI of 35 to 40 showed an astounding four-fold increase in HCC risk. Even a little elevation in BMI in the 25-30 overweight range considerably increased the risk of death due to HCC.
The development of HCC depends on the increased production of tumor-promoting cytokines IL-6 and TNF, which cause inflammation of the hepatic tissue. These cytokines also activate STAT3, which is a cancerous transcription factor.
Besides liver cancer, excessive weight is linked to other forms of cancer such as that of Breast, Colorectal, Uterus, Kidney, Pancreas, Prostate, Gallbladder and more.
Overall, more than 90,000 deaths due to cancer per year in the United States are linked to excessive body weight.