Guest post by Ilana Kersch, MS RD CDN, Senior Dietitian at the Mount Sinai Hospital. Ilana works as part of the inpatient liver transplant team in conjunction with the Recanati Miller Transplant Institute, and provides nutrition care for patients pre- and post-hepatobiliary surgery.
In recent decades, non-alcoholic fatty liver disease (NAFLD) has become an important cause of liver disease in the US due to its association with rising prevalence of obesity and type 2 diabetes. It is estimated that approximately 30% of the US population now has some degree of non-alcoholic fatty liver, and ~2- 5% of the population have fatty liver which has progressed to non-alcoholic steatohepatitis (NASH). If untreated, NAFLD and NASH can progress to liver cirrhosis and malignancy, and is quickly becoming a major indication for listing for liver transplant.Currently, there are no medications on the market which directly treat NAFLD. There is ample ongoing research looking into the effects of both drug therapies and nutritional compounds on fatty liver. Vitamin E and pioglitazone have been shown to decrease inflammation and hepatic steatosis in patients with biopsy-confirmed NASH who do not have cirrhosis, but these results cannot be generalized to other populations. Many other pharmacologic agents are in preliminary research, including non-insulin hypoglycemic agents (rosiglitazone, metformin, further research on pioglitazone), “hepato-protective” agents (pentoxifylline, ursodeoxycholic acid), and lipid-lowering agents (statins, fenofibrates). Compounds with antioxidant properties such as vitamins C and E, niacin, resveratrol (red wine extract), DHA (omega-3 fatty acid), and caffeine are potential future treatment options, as are other nutritional supplements such as non-essential amino acids and probiotics. However, none of these medications are FDA-approved explicitly to reduce steatohepatitis, and research shows limited efficacy (at most, 50% of those studied).
The primary treatments for NALFD focus on improving insulin sensitivity and markers of metabolic syndrome. Lifestyle intervention is the cornerstone of both NAFLD prevention and treatment. In overweight and obese patients, even modest weight loss of 3 to 5% of body weight (for example, losing 6-10 pounds from a starting weight of 200 pounds) has been shown to reduce steatosis, and those who lose at least 7% show decreased inflammation. In a randomized controlled trial conducted with NASH patients, subjects who participated in an intensive structured program lost more weight and had greater reduction in transaminase levels when compared to the control group who received physician education alone. In another interventional trial, 64% of subjects who received regular diet and exercise counseling from a dietitian had resolution of NAFLD on repeat imaging after 12 months, as compared with only 20% of the control group who were simply told to lose weight. Certain diet and physical activity patterns may be particularly effective for treatment of NAFLD. In a 6-week crossover trial, following a Mediterranean diet pattern (replacing fat from red meat and butter with olive oil, increasing intake of plant-based foods such as fresh fruits and vegetables, whole grains, legumes, nuts and seeds)resulted in decreased steatosis and increased insulin sensitivity when compared with a high-carbohydrate, lower-fat “Western”-style diet with the same daily Calories. In another isocaloric diet study, patients who restricted carbohydrate intake lost the same amount of weight as the higher carbohydrate group, but also had significantly less hepatic fat after 2 weeks. Cardiovascular exercise may be more beneficial than resistance training; other studies suggest that any form of physical activity may help reduce fatty liver regardless of concurrent weight loss. Alcohol reduction or abstinence is strongly recommended.
Fortunately, NAFLD is reversible in patients who implement these lifestyle changes. Working with a multidisciplinary team is an ideal approach; including a dietitian will provide a structured nutrition plan and follow up visits, which can help with long-term adherence and weight maintenance.