Effectiveness of exercise in hepatic fat mobilization in nonalcoholic fatty liver disease: Systematic review

AIM: To investigate the efficacy of exercise interventions on hepatic fat mobilization in non-alcoholic fatty liver disease(NAFLD) patients.METHODS: Ovid-Medline, Pub Med, EMBASE and Cochrane database were searched for randomized trials and prospective cohort studies in adults aged ≥ 18 which investigated the effects of at least 8 wk of exercise only or combination with diet on NAFLD from 2010 to 2016. The search terms used to identify articles, in which exercise was clearly described by type, duration, intensity and frequency were: "NASH", "NAFLD", "nonalcoholic steatohepatitis", "non-alcoholic fatty liver disease", "fat", "steatosis", "diet", "exercise", "MR spectroscopy" and "liver biopsy". NAFLD diagnosis, as well as the outcome measures, was confirmed by either hydrogen-magnetic resonance spectroscopy(H-MRS) or biopsy. Trials that included dietary interventions along with exercise were accepted if they met all criteria. RESULTS: Eight studies met selection criteria(6 with exercise only, 2 with diet and exercise with a total of 433 adult participants). Training interventions ranged between 8 and 48 wk in duration with a prescribed exercise frequency of 3 to 7 d per week, at intensities between 45% and 75% of VO2 peak. The most commonly used imaging modality was H-MRS and one study utilized biopsy. The effect of intervention on fat mobilization was 30.2% in the exercise only group and 49.8% in diet and exercise group. There was no difference between aerobic and resistance exercise intervention, although only one study compared thetwo interventions. The beneficial effects of exercise on intrahepatic triglyceride(IHTG) were seen even in the absence of significant weight loss. Although combining an exercise program with dietary interventions augmented the reduction in IHTG, as well as improved measures of glucose control and/or insulin sensitivity, exercise only significantly decreased hepatic lipid contents.CONCLUSION: Prescribed exercise in subjects with NAFLD reduces IHTG independent of dietary intervention. Diet and exercise was more effective than exercise alone in reducing IHTG.

Interrelationship between physical activity and depression in nonalcoholic fatty liver disease

BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is associated with a sedentary lifestyle and depressive symptoms.It is also well established that physical inactivity and depressive symptoms are related.However,an investigation of the interaction between all of these factors in NAFLD has not been previously conducted.AIM To investigate the interrelationship between physical inactivity and depressive symptoms in individuals with NAFLD.METHODS Data from the Rancho Bernardo Study of Healthy Aging were utilized.589 individuals were included in the analyses(43.1%male;95.8%non-Hispanic white;aged 60.0±7.0 years).NAFLD was defined by using the hepatic steatosis index,depression using the Beck Depression Inventory,and physical activity by selfreport of number of times per week of strenuous activity.Multivariable generalized linear regression models with Gamma distribution were performed to investigate the proposed relationship.RESULTS About 40%of the sample had evidence of NAFLD,9.3%had evidence of depression,and 29%were physically inactive.Individuals with NAFLD and depression were more likely to be physically inactive(60.7%)compared to individuals with neither NAFLD nor depression(22.9%),individuals with depression without NAFLD(37.0%),and individuals with NAFLD without depression(33.3%).After accounting for various comorbidities(i.e.,age,sex,diabetes,hypertension,obesity),individuals with NAFLD and higher levels of physical activity were at a decreased odds of having depressive symptoms[16.1%reduction(95%confidence interval:-25.6 to-5.4%),P=0.004],which was not observed in those without NAFLD.CONCLUSION Individuals with NAFLD have high levels of physical inactivity,particularly those with depressive symptoms.Because this group is at high risk for poor outcomes,practitioners should screen for the coexistence of depressive symptoms and NAFLD.This group should receive appropriate interventions aimed at increasing both participation and levels of intensity of physical activity.