Introduction
According to Shaker (2014), non-alcoholic fatty liver disease (NAFLD) is a disease occurring when fat is deposited in the liver due to causes other than excessive alcohol use. This is a very common disorder and refers to a group of conditions where there is accumulation of excess fat in the liver of people who drink little or no alcohol. The most common form of NAFLD is a non serious condition called fatty liver. In fatty liver, fat accumulates in the liver cells. Although having fat in the liver is not normal, by itself it probably does not damage the liver (Rinella, 2015).
A small group of people with NAFLD may have a more serious condition named non-alcoholic steatohepatitis (NASH). In NASH, fat accumulation is associated with liver cell inflammation and different degrees of scarring. NASH is a potentially serious condition that may lead to severe liver scarring and cirrhosis. Cirrhosis occurs when the liver sustains substantial damage, and the liver cells are gradually replaced by scar tissue which results in the inability of the liver to work properly (Ruhl & Everhart, 2015).
Signs and symptoms of non-alcoholic fatty liver disease (NAFLD)
Most people with NAFLD have few or no symptoms. People suffering from NAFLD may complain of fatigue, malaise, and dull right-upper-quadrant abdominal discomfort. Mild jaundice may be noticed although this is rare. NAFLD is associated with insulin resistance and metabolic syndrome (obesity, combined hyperlipidemia, diabetes mellitus (type II), and high blood pressure) (Adams & Angulo, 2006).
Risk factors of non-alcoholic fatty liver disease (NAFLD)
Sanyal (2012) stated that a wide range of diseases and conditions can increase the risk of non-alcoholic fatty liver disease including:
- High cholesterol
- High levels of triglycerides in the blood
- Metabolic syndrome
- Obesity
- Polycystic ovary syndrome
- Sleep apnea
- Type 2 diabetes
- Underactive thyroid (hypothyroidism)
- Underactive pituitary gland (hypopituitarism)
- Gastric bypass surgery
Stages of non-alcoholic fatty liver disease (NAFLD)
NAFLD is very similar to alcoholic liver disease, but is caused by factors other than drinking too much alcohol. The four stages OF NAFLD are described below.
- Stage 1: Simple fatty liver (steatosis): Hepatic steatosis is stage 1 of the NAFLD. This is where excess fat builds up in the liver cells, but is considered harmless. There are usually no symptoms, and at this stage the person may not even realise it until an abnormal blood test result is received (Clark & Diehl, 2013).
- Stage 2: Non-alcoholic steatohepatitis (NASH): Only a few people with simple fatty liver go on to develop stage 2 of the condition, called non-alcoholic steatohepatitis (NASH). NASH is a more aggressive form of the condition, when the liver has become inflamed. Inflammation is part of the body’s response to injury, which suggests that cells in the liver are being damaged and that some liver cells are dying. A person with NASH may have a dull or aching pain in the top right of their abdomen (over the lower right side of their ribs), although there may be no symptoms at all (Nseir, Nassar & Assy, 2010).
- Stage 3: Fibrosis: Some people with NASH go on to develop fibrosis, which is where persistent inflammation in the liver results in the generation of fibrous scar tissue around the liver cells and blood vessels. This fibrous tissue replaces some of the healthy liver tissue, but there is still enough healthy tissue for the liver to function normally (Petersen, Dufour & Hariri, 2010).
- Stage 4: Cirrhosis: This is the most severe stage, where bands of scar tissue and clumps of liver cells develop. The liver shrinks and becomes lumpy (known as cirrhosis). Cirrhosis tends to occur after the age of 50-60, following many years of liver inflammation associated with the early stages of the disease. However, this can happen much earlier in some people. People who have type 2 diabetes are at the greatest risk of developing cirrhosis of the liver caused by NAFLD. The damage caused by cirrhosis is permanent and cannot be reversed. Cirrhosis progresses slowly, over many years, gradually causing your liver to stop functioning. NAFLD can also lead to primary liver cancer (hepatocellular carcinoma). This is what is known as liver failure (Shen & Fan, 2013).
Screening/diagnosis of non-alcoholic fatty liver disease (NAFLD)
The diagnosis of NAFLD is usually first suspected in an overweight or obese person who is found to have mild elevations in their liver tests during a routine blood testing or incidentally detected on radiologic investigations such as abdominal ultrasound or CT scan (Raziel & Goitein, 2015).
The diagnosis of NAFLD is confirmed by imaging studies, most commonly a liver ultrasound, showing accumulation of fat in the liver. Fat accumulation in the liver can also be caused by excess alcohol intake, certain medications, viral hepatitis, autoimmune liver disease, and metabolic or inherited liver disease. These need to be excluded as causes of fatty liver disease in order to confirm the diagnosis of NAFLD.
Currently, the only reliable way of telling whether a person has NASH or simple fatty liver is by a liver biopsy (Papandreou & Rousso, 2007). In this procedure, a small needle is inserted through the skin after local anesthesia is given to obtain a small piece of the liver for microscopic evaluation. NASH is diagnosed when examination of this piece of liver under the microscope shows fatty infiltration of the liver in addition to inflammation and different degrees of scarring. If only fat is present, then the diagnosis of simple fatty liver is made. The liver biopsy provides essential information regarding the degree of scarring within the liver, which would not be apparent on a blood test, ultrasound, or an x-ray alone.
Management of non-alcoholic fatty liver disease (NAFLD)
Management of NAFLD is done through diet, exercise, and antiglycemic drugs may alter the course of the disease. General recommendations include improving metabolic risk factors and reducing alcohol intake (Adams & Angulo, 2006).
- Diet (nutrition): Treatment of NAFLD typically involves counseling to improve nutrition and consequently body weight and composition. Specifically, avoiding food containing high-fructose corn syrup and trans-fats is recommended. Epidemiological data have suggested that coffee consumption may be associated with a decreased incidence of NAFLD and may reduce the risk of liver fibrosis in those who already have NAFLD/NASH. Olive oil consumption is also a reasonable dietary intervention. Avocados may also improve other areas of cardiovascular health (i.e., lipid profile) and their addition to a balanced diet is reasonable (Ashutosh, 2012).
- Exercise: Gradual weight loss may improve the process in obese patients; rapid loss may worsen NAFLD. Specifically, walking or some form of aerobic exercise at least 30–45 minutes daily is recommended (Ashutosh, 2012).
- Medication: Insulin sensitizers are commonly used to combat insulin resistance in those with NAFLD. Improvements in liver biochemistry and histology in patients with NAFLD through treatment with statins have also been recommended for use in treating dyslipidemia for patients with NAFLD (Raziel & Goitein, 2015).
Conclusion and recommendations
Developing non-alcoholic fatty liver disease (NAFLD) could mean a very severe health challenge as it can develop into cirrhosis which could cause an irreversible damage to the liver with its associated consequences. Based on this, it is recommended that NAFLD should be prevented through:
- Choosing a healthy diet: It is advisable for individuals to choose a healthy plant-based diet that is rich in fruits, vegetables, whole grains and healthy fats.
- Maintaining a healthy weight: For people who are overweight or obese, it is advisable for them to reduce the number of calories they eat each day and get more exercise. While people with healthy weight should work to maintain it by choosing a healthy diet and exercising.
- Exercise: Exercising most days of the week can help to prevent NAFLD.
References
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Ashutosh, S. (2012). Nutritional Recommendations for Patients with Non-Alcoholic Fatty Liver Disease: An Evidence Based Review. Nutrition Issues in Gastroenterology, Series 12:74-6.
Clark, J. M. & Diehl, A. M. (2013). Nonalcoholic fatty liver disease: an under-recognized cause of cryptogenic cirrhosis. JAMA 289 (22): 3000–4.
Nseir, W., Nassar, F. & Assy, N. (2010). Soft drinks consumption and nonalcoholic fatty liver disease. World Journal of Gastroenterology 16 (21): 2579–2588.
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Petersen, K. F., Dufour, S. & Hariri, A. (2010). Apolipoprotein C3 Gene Variants in Nonalcoholic Fatty Liver Disease. N. Engl. J. Med. 362 (12): 1082–9.
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Shaker, M. (2014). Liver transplantation for nonalcoholic fatty liver disease: New challenges and new opportunities. World journal of gastroenterology 18 (14): 5320.
Shen, L. & Fan, J. (2013). Prevalence of non-alcoholic fatty liver among administrative officers in Shanghai: an epidemiological survey. World J Gastroenterol 9: 1106–10.
