Efficacy of dietary and physical activity intervention in non-alcoholic fatty liver disease: a systematic review

Abstract

BackgroundNon-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, with prevalence above 30% in many adult populations. Strongly associated with obesity, weight loss through diet and physical activity is the mainstay of its management. Weight loss can be difficult to achieve and maintain however, and uncertainty exists as to which lifestyle changes are most effective.ObjectiveThe aim of this work was to systematically evaluate randomised controlled trials assessing diet, exercise or combination interventions aimed at reducing steatosis or markers of NAFLD activity.DesignMedline, Scopus and Cochrane databases were searched from 1 January 1980 through to 31 July 2016, for intervention trials assessing the effects of diet, weight loss, exercise or any combination thereof, on NAFLD disease markers in human adults. Risk of publication bias and study quality was assessed using the American Dietetic Association Quality Criteria Checklist.ResultsFrom a total of 1710 identified records, 24 articles met the inclusion and exclusion criteria; 6 assessed weight loss using dietary restriction, 10 assessed exercise and 8 were combination interventions. While all of the trials demonstrated significant reduction in steatosis and/or markers of NAFLD activity, combination interventions appear to be the most effective at improving NAFLD. Results suggest that 5–10% weight loss using a modestly hypocaloric diet of 500 kcal less per day than calculated energy requirement, in combination with 30–60 min exercise on 3–5 days per week should be recommended.ConclusionsWe conclude this amount of weight loss is achievable in the trial setting but is challenging in the clinical environment. High-intensity, multidisciplinary intervention in specialist clinics is likely to be required in order to manage NAFLD by lifestyle modification alone. This systematic review protocol was registered prospectively at PROSPERO as CRD42016032764.

From sugar to liver fat and public health: systems biology driven studies in understanding non-alcoholic fatty liver disease pathogenesis

“…The vast majority of adults in developed countries consume excess energy from foods high in both sugar and fat, fundamentally contributing to increasing obesity and NAFLD. Where low-fat v. lowcarbohydrate has been examined in a NAFLD context, the results are similar to that seen in the meta-analysis of weight loss trials in diabetes (72) ; whereas low carbohydrate may induce a greater weight loss in the short term (12 weeks), in the longer term (≥12 months) the net weight loss tends to be similar to that from low-fat (68,71) .…”

“…This includes eating a healthy diet and increasing physical activity to prevent and resolve NAFLD, regardless of BMI, as advised by both the UK National Institute for Health and Care Excellence (8) and the European Association for the Study of the Liver (7) . Significant reduction in steatosis and hepatic markers of NAFLD have generally been observed with 5-10 % weight loss (68,69) ; although weight reductions of >10 % may be required for resolution of NASH and reducing fibrosis and portal inflammation (70) . In general, combining dietary and physical activity interventions appears most effective, as are interventions of longer duration and greater intensity (multicomponent; more contact time, ≥14 times in 6 months); although trial heterogeneity can confound systematic review (68,69,71) .…”

“…Significant reduction in steatosis and hepatic markers of NAFLD have generally been observed with 5-10 % weight loss (68,69) ; although weight reductions of >10 % may be required for resolution of NASH and reducing fibrosis and portal inflammation (70) . In general, combining dietary and physical activity interventions appears most effective, as are interventions of longer duration and greater intensity (multicomponent; more contact time, ≥14 times in 6 months); although trial heterogeneity can confound systematic review (68,69,71) . Because achieving and maintaining 5-10 % weight loss is a significant challenge for many (69,72) , a pertinent question is whether or not improving the nutritional quality of the diet and/ or increasing physical activity may improve NAFLD in the absence of weight loss (73) .…”

“…While the focus of this review is the role of nutrition and dietary modification, increasing physical activity is an important component of lifestyle change aimed at weight loss and clinical improvement of NAFLD. Randomised clinical trials assessing the effects of resistance training, aerobic exercise or a combination of both have reported improvements in liver enzyme levels and reduced intrahepatic TAG measured by magnetic resonance spectroscopy (68,74) . Positive effects have been reported in patients engaging in physical activity only once weekly (75) , and meta-analysis shows this to be independent of significant weight change (74) .…”

Papel da alça ECA2/Ang 1-7/Mas na prevenção da doença hepática gordurosa não alcoólica por meio do treinamento físico aeróbio

“…Entretanto, o treinamento físico aeróbio (TFA) realizado cinco vezes por semana, durante três meses, pode exercer efeito protetor e reduzir o dano tecidual hepático, reduzir a insulinemia e os níveis séricos de citocinas pró-inflamatórias (BHAT et al, 2012;SCHULTZ et al, 2012). Por isso, o TFA tem sido amplamente recomendado como parte do tratamento e prevenção de prejuízos metabólicos (BACCHI et al, 2013;LINDEN et al, 2014;POETA et al, 2017), pois aumenta a sensibilidade à insulina (BHAT et al, 2012), melhora a oxidação de lipídios, diminui o peso corporal e os danos morfofuncionais hepáticos (BOTEZELLI et al, 2010;KENNEALLY et al, 2017).…”