Why is nonalcoholic fatty liver disease important?
NAFLD is important for several reasons. First, it is a common disease, affecting approximately 30% of the population and is increasing in prevalence. Second, NASH is an important cause of serious liver disease, leading to cirrhosis and the complications of cirrhosis–liver failure, gastrointestinal bleeding, and liver cancer. Third, NAFLD is associated with other very common and serious non-liver diseases, perhaps the most important being cardiovascular disease that leads to heart diseaseand strokes. Fatty liver probably is not the cause of these other diseases, but is a manifestation of an underlying cause that the diseases share. Fatty liver, therefore, is a clue to the presence of these other serious diseases which need to be addressed.
Weight and exercise are among the most promising of treatments for NAFLD. It does not take large amounts of weight loss to result in a decrease in liver fat. A 7% decrease in weight may be enough. Vigorous exercise results in a reduction of liver fat and also may reduce the inflammation of NASH. The long-term effects of weight loss and exercise on the important development of cirrhosis and its complications are unknown. Nevertheless, at the present time, the best theoretical approach to NAFLD is weight loss and vigorous exercise. Unfortunately, only a minority of patients are able to accomplish these.
What is the relationship between nonalcoholic fatty liver disease and cardiovascular disease?
As mentioned previously, cardiovascular disease, especially heart attacks and strokes, is commonly seen in patients with fatty liver. In fact, cardiovascular causes of death occur more frequently than liver-related deaths. Whereas the components of the metabolic syndrome are risk factors for cardiovascular disease, NAFLD has been found to be a risk factor that is independent of the metabolic syndrome, increasing the risk two-fold. Since the means of treating NAFLD are limited, it is important that the manifestations of the metabolic syndrome – obesity, diabetes, high blood pressure, dyslipidemia (abnormalities of fats or lipids in the blood) – should be aggressively treated.
What diseases are associated with nonalcoholic fatty liver disease?
The diseases of the metabolic syndrome that are associated with NAFLD have already been discussed. Other associations exist including fatty pancreas, hypothyroidism, polyps of the colon, elevated blood uric acid, vitamin D deficiency, polycystic ovaries, and obstructive sleep apnea. For example, 50% of patients with NAFLD have obstructive sleep apnea, and more than 90% of patients with obstructive sleep apnea have NAFLD. Associations do not prove causation, and in most cases it is not clear why the associations exist–whether the associations are due to a causal relationship or they reflect an underlying common cause.
In most patients nonalcoholic fatty liver disease causes no symptoms. Nonalcoholic fatty liver disease often is discovered when routine blood tests show slightly elevated levels of liver enzymes (ALT and AST) in the blood. Another way in which nonalcoholic fatty liver disease is discovered is when ultrasound examination of the abdomen is done for other purposes, say for looking for gallstones, and fat is found in the liver. In the late stages of non alcoholic fatty liver disease, the development of cirrhosis can lead to failure of the liver, swelling of the legs (edema), accumulation of fluid in the abdomen (ascites), bleeding from veins in the esophagus (varices), and mental confusion (hepatic encephalopathy). Patients with cirrhosis caused by Nonalcoholic fatty liver disease also may be at risk of developing liver cancer (hepatocellular carcinoma, HCC).
Care for Your Liver
Here are the proven ways to avoid wrecking your liver:
Don’t drink a lot of alcohol. Alcohol can damage liver cells, leading to the swelling or scarring that becomes cirrhosis, which can be deadly.
According to the federal government’s Dietary Guidelines for Americans, moderate alcohol use is defined as having up to one drink per day for women and up to two drinks per day for men. Stay at or under this to keep from harming your liver.
Eat a healthy diet and get regular exercise. A condition called nonalcoholic fatty liver disease (NAFLD) also can lead to cirrhosis. It comes from being overweight, having diabetes, or having high levels of fat in your blood. NAFLD affects about 25% of people in the U.S. It can be avoided through weight loss if you’re overweight, getting regular exercise, and eating a balanced diet.
Stay away from medicines (or combinations of medicines) that harm the liver. Cholesterol drugs and the painkiller acetaminophen (Tylenol) can be toxic to the liver if too much is taken over time or at once. You may be taking more Tylenol than you realize; it’s found in hundreds of drugs like cold medicines and prescription pain medicines. Certain combinations of drugs can be toxic to the liver; so can taking some medicines while drinking alcohol. Talk to your doctor or pharmacist about what medicines shouldn’t be combined with each other or alcohol. And always follow dosage information.
Be aware of hepatitis and how it is transmitted. Hepatitis is a virus that causes the liver to become inflamed. There are several different types. Hepatitis A is transmitted by water or food that’s been contaminated with bacteria found in feces. It usually gets better on its own. Hepatitis B and C are transmitted through blood and body fluids. If untreated, it can lead to cirrhosis, liver cancer, and liver failure. Hand washing and avoiding places that don’t seem clean can prevent hepatitis A. To prevent hepatitis B and C, don’t share items like toothbrushes, razors, or needles, limit the number of sex partners you have, and always use latex condoms if you have more than one partner.