Fatty Liver Disease
The obesity epidemic has resulted in a surge in the number of chronic diseases, from type-2 diabetes and hypertension to heart disease and cancer. Recently, health experts have identified an association with yet another chronic condition related to obesity: Nonalcoholic Fatty Liver Disease (NAFLD), one of the most common chronic liver illnesses in industrialized countries. The spectrum of this disease ranges from a simple form (steatosis) with a benign prognosis, to a potentially progressive form, nonalcoholic steatohepatitis (NASH), which may lead to liver cirrhosis. Approximately 5-10% of patients progress from the simple form to NASH.
Physicians had usually associated fatty liver with excessive drinking or chronic viral hepatitis. However, epidemiologists have found an increasing number of patients diagnosed with liver fat in the absence of those two factors. While this phenomenon has traditionally been more prevalent in the western world, according to a 2007 article published in the Journal of Gastroenterology and Hepatology, the prevalence of NAFLD in Asia is between 12% and 24%. Furthermore, the prevalence in China and Japan has nearly doubled in the last 10-15 years.
How is NAFLD diagnosed?
The diagnosis is often made by ultrasound which detects an accumulation of fat in the liver. Blood tests may show an elevation of liver enzymes (aminotransferases), suggesting inflammation of the liver (hepatitis). Unfortunately, as researches are not certain of the exact cause of NAFLD, physicians are unable to offer a definitive treatment for this. However, studies have uncovered some interesting associations, generating some plausible hypotheses suggesting lifestyle as having an important role in NAFLD.
What causes fatty liver?
The best identified underlying issue appears to be calorie abundance characteristic of a typical Western-style diet rich in processed foods, simple carbohydrates and saturated fat. When this is coupled with inactivity, it results in weight gain, ultimately leading to an increased prevalence of NAFLD in both adults and children.
A study published in the Journal of Hepatology in 2010 found that 7-10% weight reduction from intensive lifestyle changes can not only improve aminotransferase levels but also improve the way liver tissue looks under a microscope. Closer to home, a study conducted in the Chengyang District of Qingdao, China and published in 2012 in the World Journal of Hepatology, also showed that intensive lifestyle interventions over a 6-12 month period can result in improvements in NAFLD. These and numerous other studies suggest that weight loss via healthy lifestyle is the best way to reduce progression or even improve NAFLD in patients that are overweight.
The reason why being overweight plays such a major role in NAFLD is not entirely understood at present. The most popular theory is related to “insulin resistance.” This thinking is based on the fact that being overweight makes the body resistant (less sensitive) to the effects of insulin – a hormone that regulates your body’s blood sugars. This insensitivity to insulin means that the body needs to produce more insulin simply to keep blood sugars within normal range. Insulin resistance is one reason why being overweight is a major risk factor for diabetes. In addition to damaging other organs in the body, this chronic bombardment of the liver from high levels of insulin causes liver damage, ultimately resulting in NAFLD.
It is important to remember, however, that not every overweight patient has fatty liver and not all patients with fatty liver are overweight, suggesting that genetic predispositions as well as other factors, independent of weight, also play important roles. For example, high cholesterol and/or triglyceride levels, soft drink consumption, type-2 diabetes, and high blood pressure have also been identified as risk factors for NAFLD.
Are there any treatments for NAFLD?
While there are no established treatments or methods for intensive lifestyle modification, the following are some strategies that may help to prevent NAFLD, reduce its progression or even improve its status.
1) Gradual weight loss: If you have been told by your physician that you are overweight or obese, it is important to reduce your calorie intake and increase physical activity. This will help to simultaneously reduce most of the major risk factors associated with NAFLD. As a general rule, reducing intake by 500-1,000 calories per day will result in weight loss of about 1-2 pounds per week. To put this into perspective, an average blueberry scone is about 400 calories; once ounce potato chips -150 calories; and butter croissant – 300 calories. Dietary strategies should include reducing refined carbohydrate (such as white sugar and white flour), processed food, cholesterol and saturated fatty acid intake, while increasing consumption of whole foods (fruits, vegetables, beans, peas, seeds and nuts). Current recommendations encourage 150 minutes of moderate intensity physical activity per week.
2) Consume less soft drinks: In addition, recent studies, including one published in 2009 in the Journal of Hepatology, have shown that soft-drink consumption (both regular and diet), to be a strong predictor of developing NAFLD, independent of other risk factors. This is thought to be primarily due to caramel coloring as well as high levels of a sugar called fructose found in the regular versions while diet versions have high levels of aspartame (an artificial sweetener).
3) Green tea: According to a 2011 article in Nutrition Reviews, there is strong evidence that green tea extract can mitigate the development and/or progression of NAFLD in mice. Researchers feel the studies compelling enough to warrant trials in humans. As the safety profile of green tea extract has not yet been determined, the routine consumption of high doses cannot be recommended. Good human studies have not yet been conducted to determine the amount of actual green tea needed to be consumed to produce similar beneficial effects as green tea extract on the liver. One study published in 2005 in the British Medical Journal found improved liver transaminase levels in patients that consumed 10 or more cups of green tea per day; probably a bit too much green tea for most individuals to sustain long-term. In any case, drinking a few cups a day will likely offer some benefit.
4) Coffee: Multiple studies have shown the protective effect of this popular drink on the liver. Researchers from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) found that hepatitis C patients who consumed the equivalent of 2.25 cups of coffee per day had less severe liver damage from the hepatitis C. A 2012 study published in the journal Hepatology indicates that coffee consumption can mitigate the progression of NAFLD as well. Although studies are still needed to determine exactly how much coffee needs to be consumed in cases of NAFLD, most experts would not discourage moderate coffee intake in those with NAFLD, based on current available evidence.
5) Alcohol: According to a 2012 review published in the American Journal of Gastroenterology, until more good studies are conducted, “people with NAFLD should avoid alcohol of any type or amount.”
6) Do not take unnecessary medications
Despite the significant amount of evidence linking it to obesity, there is still a great deal to be learned regarding NAFLD. However, based on the best available medical evidence, regardless of whether or not you have NAFLD, it is always wise to maintain a balanced and healthy pattern of living to preserve your liver and your overall health.
“Effect of changes on body weight and lifestyle in nonalcoholic fatty liver disease.” Journal of Hepatology. 2005; 43: 1060-1066.
“Lifestyle intervention in non-alcoholic fatty liver disease in Chengyang District, Qingdao, China.” World Journal of Hepatology. July 27, 2012; 4(7): 224-230.
“What are the risk factors and settings for non-alcoholic fatty liver disease in Asia-Pacific?” Journal of Gastroenterology and Hepatology. June 2007; 22(6): 794-800.