“Doctor, my diabetes control is much better but my liver tests are abnormal,” said the 50-year-old overweight woman. “I am very worried. What should I do about it?” Her reports showed a mild elevation of liver enzymes. Ten years ago, I would have dismissed her concern as unimportant. ‘”It’s just a fatty liver,” I would have said, and asked her to move on. But science is ever-evolving and teaches us new things all the time. Our perspective about fatty liver has undergone a sea change in the last decade. For decades, fat in the liver was considered to be harmless and passive. We now realise that non-alcoholic fatty liver disease (NAFLD) is the commonest chronic liver disease and can have serious implications.
What is fatty liver?
Simply put, it means excess fat in the liver, which is a large organ on the right side of our abdomen below the rib cage. It receives a generous blood supply, which helps it extract energy from the food we eat and also helps it rid our body of toxins. Some fat is present in the liver normally, but this is less than 5 to 6 per cent as measured by sophisticated tools like MRI scans or liver biopsy. Fat in excess of this constitutes fatty liver disease, called non-alcoholic fatty liver disease (NAFLD) in medical parlance. While not everyone with fat in the liver develops complications, it can lead to inflammation (steatohepatitis or NASH) in 5 to 10 per cent cases, followed by scarring or fibrosis, cirrhosis, liver failure and in rare cases even liver cancer.
But fat in the liver does not just impact that organ. It plays a central role in diverse body processes and fat in the liver can have implications much beyond the liver, like increasing the risk of diabetes, heart disease and strokes. What makes it more complex is that it is not a one way street. Fat in the liver increases insulin resistance. As insulin resistance increases, the pancreas tries to overcome it by working harder and gradually gets fatigued, accelerating the development of Type 2 diabetes. Once people have diabetes, they have an even greater risk of developing fatty liver. In fact, 80 per cent of those with Type 2 diabetes have fatty liver. When fat accumulates in the liver, it makes diabetes harder to control by increasing insulin resistance. NAFLD and diabetes can exacerbate each other and make both conditions harder to manage. The condition is strongly related to obesity and has been linked to hypertension and high cholesterol too.
How is NAFLD diagnosed?
Fatty liver unfortunately produces no symptoms in the early stages and often remains undiagnosed till cirrhosis of the liver has set in. Obesity increases the chances of developing NAFLD but the lean are not immune to it. One clue is the detection of fat in the liver on ultrasound, another is the finding of abnormal blood liver function tests. But people with neither of these features may also have NAFLD. Greater use of a liver elastography test (“fibroscan”) has greatly enhanced the capability to diagnose NAFLD and the degree of fibrosis. The test takes a few minutes and is totally non-invasive. Some cases may require MRI, which is more accurate but also more expensive and time-consuming. A final diagnosis can be made by a liver biopsy, an invasive procedure that is not commonly used in a clinical setting.
Who should undergo tests for NAFLD?
In my clinical practice, I ask for an ultrasound liver and liver function tests annually, followed by a liver fibroscan if either of these is abnormal, or the patient is obese.
How should NAFLD be managed?
Shedding those extra kilos is the first step. Losing 5 to 10 per cent of body weight can improve the condition of the liver substantially, and can reverse the condition in its early stages at times. Consuming a healthy diet and regular exercise are important. A diet rich in vegetables, dal and beans, whole grains (as opposed to refined ones), nuts and lean proteins like chicken and fish is recommended, while sweets, white bread/maida and fried foods are best avoided. Alcohol can worsen NAFLD and is to be strictly avoided.
Vitamin E has been used with limited benefit and long-term safety is not established. Among the anti-diabetic medications, Pioglitazone is effective but it is not widely used because of side effects like weight gain. A resurgence of interest is taking place in Pioglitazone, using lower doses than earlier to minimise side effects. Anti-diabetic drugs that act via the GLP1 receptor (for example, Liraglutide, Dulaglutide, Semaglutide), and help in weight loss, have been shown to reduce liver fat too. SGLT2 inhibitors are a class of anti-diabetics that act by throwing out blood glucose via urine. Like drugs that act via the GLP1 receptors, SGLT2 inhibitors also help in losing weight. Both these groups have been studied by us and have been found to be effective in reducing liver fat. The long-term impact of these drugs on liver inflammation and fibrosis is still being studied. Since cholesterol has also been linked to NAFLD, use of statins has also been shown to be beneficial in some studies. Besides these, there are several innovative molecules being developed, but none is in clinical use as yet.
What should you do if you have diabetes and are diagnosed with fatty liver?
Diet and exercise remain the basics of management. Weight loss and better control of diabetes are the key to success. Choosing the right antidiabetic medication can also be very helpful.
(The author has been honoured with a Padma Bhushan)
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