Non-alcoholic Fatty Liver Disease (NAFLD) and Non-alcoholic Steatohepatitis (NASH)

Non-alcoholic Fatty Liver Disease (NAFLD) and Non-alcoholic Steatohepatitis (NASH)

Numerous population-based scientific studies suggest a sedentary lifestyle as the prime reason for many of the chronic illnesses that we face today. A sedentary lifestyle has little or no physical activity (sometimes irregular physical activity). Approximately, 31% of the world population aged 15 or above live their life with insufficient physical activity and this is known to contribute to the mortality of approximately 3.2 million persons per year across the globe. Sedentary lifestyle includes sitting, reading, socialising online (generally internet), watching television, computer use or mobile phone for much of the day with little or no physical exercise. This lack of physical exercise can contribute to or be a risk factor for many diseases, such as cardiovascular disease, migraines, many forms of cancer, diabetes, obesity, fatty liver, depression, high blood pressure, lipid disorders, etc.
One of the health issues emerging at a much faster rate is fatty liver disease, which may end up in liver cancer. Fatty liver is defined and characterised by the excessive accumulation of fat in the liver which impairs the functioning of the liver. There are two types of fatty liver disease. One is Alcoholic Fatty Liver Disease (AFLD), where alcohol intake is the prime cause. The other is Non-Alcoholic Fatty Liver Disease (NAFLD), where diet and lifestyle are important causes.
NAFLD is strongly associated with sedentary lifestyle and is a strong risk factor for the development of obesity and diabetes. Some individuals with NAFLD may develop an aggressive form of the disease called Non-Alcoholic Steatohepatitis (NASH), which is characterised by liver inflammation and which may progress to fibrosis, cirrhosis and end-stage liver cancer. The damage becomes similar to the damage caused by heavy alcohol drinking. The prevalence of NAFLD across the globe is increasing at the same rate as that of obesity and is estimated to be about 25% globally. The Middle East is showing 32% prevalence, South America at 31%, Asia at 27%, Europe at 24% and USA at 23%.

Complications and Symptoms
The major complication of NAFLD and NASH is cirrhosis, which is characterised by the scarring of the liver tissue. Cirrhosis is basically a response to liver injury, especially inflammation, and if not interrupted, the continued inflammation can consume whole of the liver tissue and may lead to further complications such as:
1. Fluid build-up in the abdomen (Ascites)
2. Swelling of esophageal veins, which may rupture and lead to internal bleeding.
3. Enlargement of liver called as hepatomegaly
4. Confusion, drowsiness and slurred speech
5. End-stage liver cancer, which means that the liver has stopped functioning.
6. Enlarged breasts in men, enlarged spleen, red palms, yellowing of skin and eyes (jaundice).

Diagnosis of NAFLD and NASH
As NAFLD is asymptomatic in most cases, NAFLD frequently comes to medical attention when tests are done for other complications. There are various diagnostic tests that are currently used to pinpoint NAFLD and NASH and also the severity of the disease. These tests include:
1. Blood Tests: These include complete blood count, liver functions test, Lipid profile, fasting blood sugar, HbA1C levels.
2. Imaging Procedures: These include: A): Abdominal ultrasound, usually done as a routine test when liver disease is suspected. B): Computerised Tomography (CT) scan or Magnetic Resonance Imaging (MRI). C): Transient elastography generally called FibroScan, used to measure the liver stiffness and hence giving us the idea about the scarring or the fibrosis of the liver.
3. Liver tissue examination/biopsy: If the above tests are not conclusive, the doctor may recommend a procedure to remove the sample of liver tissue for detailed examination.

What causes NAFLD and NASH?
There is still limited understanding of why some people develop fatty liver while others do not though fed on the same diet. This is for researchers to look into. One reason suggested is different gut microbiota, but the discussion is beyond the scope of this article. Similarly, there is limited understanding how fatty liver progresses to cirrhosis and liver cancer. However, there are certain potential causes: sedentary lifestyle, diet rich in saturated fatty acids, overweight or obesity, high blood sugar, insulin resistance (where cells fail to take up sugar in response to insulin). These combined appear to promote the deposition of fat in the liver.

Risk Factors
A risk factor is defined as an attribute or characteristic that increases the likelihood of developing a disease. The risk factors for the development of NAFLD include: high cholesterol, high levels of triglycerides in blood, metabolic syndrome, obesity, polycystic ovary syndrome, type II diabetes, underactive thyroid (hypothyroidism), underactive pituitary gland (hypopituitarism).

Precautions and Preventive Measures
To reduce the risk of developing NAFLD and NASH, one should at least do the following:
1. Choose a healthy diet: A diet that is rich in fruits, vegetables, whole grains and healthy fats.
2. Maintain a healthy weight: If you are obese or overweight, reduce the number of calories you eat/day and get physically more active. And if you have healthy weight, work to maintain it by choosing a healthy diet and exercise.

Treatment of NAFLD and NASH
The first line of treatment is usually weight loss through a combination of healthy diet and physical activity (exercise). There is no FDA approved drug for fatty liver disease available in the market. One other option that can be considered is:
Vitamin E: Some studies suggest that Vitamin E supplements may be helpful for people with liver damage from Non Alcoholic Fatty Liver Disease. But there is a strong caution. Vitamin E has been linked with increased risk of death and, in men, increased risk of prostate cancer. So, be cautious and consult your doctor.

Take-home message
1. Non Alcoholic Fatty Liver Disease is emerging at a greater rate than expected.
2. To avoid metabolic diseases such as diabetes and fatty liver, take precautionary measures.
3. Avoid sedentary lifestyle and increase physical activity.
4. Look for the symptoms.
5. Consult doctor.
6. Need for population-based (epidemiological) study in our state Jammu & Kashmir. In this connection, gastroenterologists need to play a leading role. This will help us understand the disease in a better way. Once we understand the problem, together we will find a solution.

The writer is Assistant Professor at Department of Biochemistry, HED, J&K. The writer has worked on understanding the basic mechanism of lipotoxicity in NAFLD and NASH at CSIR-IIIM Jammu, Group on Molecular and Cell Biology of Lipids at University of Alberta, Canada, and is currently engaged in understanding the epigenetic and autophagy crosstalk in NAFLD and NASH pathogenesis.


Leave a Reply

Your email address will not be published.