Nonalcoholic Fatty Liver Disease
Dr. Widjaja Luman
Consultant Gastroenterologist and General Physician
B Sc (St. Andrews), MB ChB (Man), MRCP (UK), M.D. (Edin),
CCST (UK), FRCP (Edin)
Nonalcoholic fatty liver disease (NAFLD) occurs when there is excessive fat deposition in the liver of people who don’t drink a lot of alcohol. The excessive fat is stored in the liver cells. NAFLD has become increasingly more common around the world, especially in Western nations. It is the most common form of chronic liver disease, affecting about one-quarter of the population.
There are two types of NAFLD. If there’s no inflammation (seen on liver biopsy as infiltration of inflammatory cells in the liver) along with the build-up of fat, the condition is known as simple nonalcoholic fatty liver. In contrast, Nonalcoholic steatohepatitis (NASH) is a type of NAFLD when build-up of excess fat in the liver is accompanied by liver inflammation. When left untreated, liver inflammation in NASH may progress to advanced scarring (cirrhosis), primary liver cancer (Hepatoma) and liver failure. This damage is similar to the damage caused by heavy alcohol use. About one quarter of people with NAFLD have NASH.
What are the causes of NAFLD?
The reason why in a group of people with NAFLD, some people have simple NAFLD while others develop NASH is not known. Several of the following factors may play a role:
- Obesity and sedentary life style.
- High cholesterol / triglyceride / blood sugar level.
- Insulin resistance
- Genetic factor. If you have a family history of fatty liver disease or diabetes mellitus, you are more likely to develop it yourself.
These risk factors appear to promote the accumulation of fat in the liver. The more the risk factors, the higher is the risk of the individual having NASH rather than simple fatty liver. Due to association of the condition with other metabolic disorders listed above, there is a proposal to change NAFLD to MAFLD (Metabolic associated fatty liver disease).
What are the symptoms of NAFLD?
Patients with NAFLD usually do not have any symptoms. They may sometime complain of vague discomfort in upper abdomen or lethargy. Those patients who have developed cirrhosis will exhibit signs of liver failure such as:
- Abdominal swelling (ascites). This is due to retention of fluid in the abdominal cavity.
- Ankle swelling
- Yellowing of the skin and eyes (jaundice)
What are the complications of NAFLD?
Fatty liver can progress through four stages:
- Simple fatty liver. There is a build-up of excess fat in the liver.
- Steatohepatitis. In addition to excess fat, there is inflammation in the liver.
- Fibrosis. Inflammation in the liver has caused scarring.
- Cirrhosis. Scarring of the liver has become widespread.
- Liver cancer
Cirrhosis is the stage when there is widespread scarring in liver. It is irreversible. Between 5% to 12% of people with NASH will progress to cirrhosis. It is important to prevent NAFLD from progressing to How can my doctor diagnose NAFLD?
Patients with NAFLD do not have symptoms and the condition is usually detected incidentally during health screening or when tests are done for other reasons. This can happen if your liver looks unusual on ultrasound or if you have an abnormal liver enzyme test.
The blood tests show elevated liver enzymes. Usually, the serum transaminases (alanine aminotransferase test (ALT) and aspartate aminotransferase test (AST) are elevated. However, these indices are seldom elevated above three times the upper limit of normal in NAFLD. Fasting blood sugar may also be elevated. Ultrasound scan of liver show fatty liver. Elevated liver enzymes indicate inflammation of liver cells. NAFLD is one potential cause of liver inflammation, but it’s not the only one.
Your doctor may order further blood test to confirm diabetes mellitus, and to exclude chronic viral hepatitis B and C, and auto immune hepatitis. Further investigation is seldom required beyond these tests. Occasionally, your doctor may order Transient elastography (also known as Fibroscan) or Magnetic resonance elastography. These two tests are for determining stiffness of liver, or degree of fibrosis or scarring.
What are the treatments?
The first line of treatment is weight loss through a combination of a healthy diet and exercise. Choose a healthy plant-based diet that’s rich in fruits, vegetables, whole grains and healthy fats. Avoid oily and sugary food. Maintain active life style with regular exercise on most days of the week (Aim for at least 30 minutes of moderate intensity exercise at least three times per week). If you are overweight, you should aim to lose 10% of body weight in six months. Improvement in risk factors of NAFLD can become apparent even if you just lose 3% to 5% of your starting weight. Weight loss (bariatric) surgery can be recommended to those patients who need to lose more drastic of weight (with BMI above 35).
Some evidence suggests vitamin E supplements may be helpful for people with NAFLD. But too much vitamin E ingestion has been linked with increased risk of death and, in men, an increased risk of prostate cancer. Vit E supplements should not exceed 400IU per day. There is also some evidence that drinking coffee 2 cups per day may be protective against liver damage. Coffee may contain some chemicals that may be protective against damage by NAFLD. Limit your alcohol intake to less than 10 units per week.
There is no drug that has been approved for NAFLD at the time of the writing of this article. However, many drugs are in research pipeline for reducing liver inflammation and scarring in liver (fibrosis).