Obesity & Non-Alcoholic Fatty Liver Disease

Obesity is a major health problem worldwide; it increases the risk of developing several chronic diseases such as:

    • Type II diabetes
    • Insulin resistance
    • Coronary heart disease – responsible for heart attacks
    • Cerebrovascular disease – responsible for stroke
    • High blood pressure
    • Gout
    • Gallstones
    • Colon cancer
    • Sleep apnea
    • Non-alcoholic fatty liver disease (NAFLD)

Obesity is defined as an excess amount of body fat that is expressed as a percentage of body weight.

Another easier way of defining obesity is by calculating the Body Mass Index (BMI). The BMI is a mathematical formula that considers both a person’s weight and height in calculating the degree of obesity.

80% of deaths related to obesity occurs in obese individuals with a BMI greater than 30. To find out what your BMI is, please refer to the Body Mass Index (BMI) table for adults, and the Body Mass Index (BMI) Index table for teens.

What is non-alcoholic fatty liver disease (NAFLD)?

NAFLD refers to a wide spectrum or a group of liver diseases that include:

    • Fatty liver (steatosis) – accumulation of fat in the liver. This is most common
    • Non-alcoholic steatohepatitis (NASH) – fat in the liver causing liver inflammation
    • Cirrhosis – irreversible, advanced scarring of the liver because of chronic inflammation of the liver

All the above are now believed to be due to insulin resistance, a condition associated with obesity. In fact, the BMI correlates with the degree of liver damage – greater the BMI, greater the liver damage.

Patients with NAFLD do not consume an excessive amount of alcohol, however since it shows the same spectrum as the liver disease due to alcohol, hence it is named as NAFLD.

Presentation & progression of NAFLD

It is the most common liver disease worldwide, affecting 10-24% of the world’s population. The disease is observed principally in developed countries. In these societies, a sedentary lifestyle, high calorie sugar and fat intake lead to a high prevalence of obesity, insulin resistance, and diabetes.

 

In most patients, NAFLD has no symptoms. It is diagnosed either when routine blood tests show slightly elevated levels of liver enzymes ALT and AST in the blood or when an ultrasound examination of the abdomen is done for other reasons e.g. for gallstones, and fat is found in the liver.

 

In the late stages of NAFLD, the development of cirrhosis can lead to failure of the liver, swelling of the legs (oedema), accumulation of fluid in the abdomen (ascites), bleeding from veins in the oesophagus (varices), mental confusion (hepatic encephalopathy) and patients may also be at risk of developing liver cancer (hepatocellular carcinoma, HCC).

 

One common cause of liver failure, and thus a common reason for transplantation of the liver, is cryptogenic cirrhosis (cryptogenic means that the cause of the cirrhosis is unknown). Doctors now believe that many patients with cryptogenic cirrhosis are patients in the late stages of NAFLD. Doctors and public health officials project that obesity related liver diseases (cryptogenic cirrhosis and liver cancer) will become the leading cause of liver failure and liver transplantation soon.

How are NAFLD and NASH treated?

Losing excess weight is the cornerstone of treatment.

Studies have found that among obese individuals with elevated transaminases, weight gain led to a further increase in the level of the liver enzymes. In contrast, a 10% loss of weight leads to a significant decrease in the levels of the enzymes, and the enzymes even may become normal. The decrease in enzymes occurred at the rate of 8% per 1% loss of body weight. In studies of patients undergoing stomach (gastric) reduction operations for morbid obesity, substantial weight loss is accompanied by a marked reduction in transaminases and a regression (improvement) of NAFLD. 

 

Doctors prescribe specific medication to treat NAFLD. Certain medicines not only help to control blood glucose in patients with diabetes, but also improve enzyme levels in patients with NAFLD. Few other medicines help to decrease the bad cholesterol and improve enzyme levels among patients NAFLD. Studies have also suggested possible benefits of certain vitamins in treating NAFLD, depending on the patient’s need, doctors decide. More studies are necessary to determine whether these medications also reduce the amount of fat and inflammation in the liver.

 

For NASH, the single most effective treatment is to simply lose weight through diet and exercise. Unfortunately, this is no easy task in a society that is dominated by a sedentary lifestyle and high-calorie, high-carbohydrate, high-fat diet. With great effort, however, weight loss is achievable. Furthermore, in view of the possible detrimental effects of fat in other liver diseases, weight loss might be added to the treatment of other liver diseases that are not primarily due to fat, such as hepatitis C. Ultimately, NASH probably can be largely prevented and eliminated by promoting healthy eating habits and active lifestyles in children, where it all begins.