Dietary Interventions in Patients With Non-alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis - PubMed (original) (raw)

Dietary Interventions in Patients With Non-alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Veera Houttu et al. Front Nutr. 2021.

Abstract

Background: With no approved pharmacotherapy to date, the present therapeutic cornerstone for non-alcoholic fatty liver diseases (NAFLD) is a lifestyle intervention. Guidelines endorse weight loss through dietary modifications, physical exercise, or both. However, no consensus exists on the optimal dietary treatment. Objectives: The aim of our systematic review and meta-analysis was to summarize and assess the evidence for applied types of dietary interventions on the liver and metabolic outcomes in patients with NAFLD, aside from any effects of exercise intervention. Methods: This systematic review was conducted according to the Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) statement guidelines. The search was conducted in PubMed, Scopus, and Cochrane databases in February 2020. Included were only dietary interventions without exercise. This study was registered at PROSPERO: CRD42020203573. Results: Eight randomized controlled trials, seven with endpoint reduction of hepatic steatosis, one with an assessment of endpoint fibrosis, were included in this systematic review, five of which were included in the meta-analysis. Mediterranean dietary interventions without energy restriction (n = 3) showed significant reduction of intrahepatic lipid content (IHL) (SDM: -0.57, 95% CI: -1.04, -0.10), but there was no significant change in alanine transaminase (ALT) (SDM: 0.59, 95% CI: -0.5, -1.68). Hypocaloric dietary interventions with foods high in unsaturated fatty acids (n = 2) led to a significant decrease in ALT (SDM: -1.09, 95% CI: -1.49, -0.69) and aspartate aminotransferase (AST) (SDM: -0.75, 95% CI: -1.27, 0.23); yet effects on steatosis could not be aggregated due to different assessment techniques. Mediterranean diet did not lead to significant changes in concentrations of gamma-glutamyl transpeptidase (γGT), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), fasting glucose or insulin, or homeostatic assessment for insulin resistance. Conclusions: In patients with NAFLD, Mediterranean and hypocaloric dietary interventions favoring unsaturated fatty acids result in improvements in IHL and transaminases. Since many dietary intervention studies are combined with exercise interventions and there is a paucity of ample-sized studies examining dietary interventions on the more advanced and clinically relevant stages of NAFLD, that is active and fibrotic NASH, with multiparametric imaging and liver histology as outcome measures, the optimal dietary invention in NAFLD remains to be defined.

Keywords: diet intervention; glucose metabolism; lipid metabolism; liver fat; liver transaminases; meta-analysis; non-alcoholic fatty liver disease; systematic review.

Copyright © 2021 Houttu, Csader, Nieuwdorp, Holleboom and Schwab.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1

Figure 1

Preferred reporting items of systematic reviews and meta-analysis (PRISMA) flow chart (34). NAFLD, non-alcoholic fatty liver diseases; non-RCT, non-randomized controlled trial; PA, physical activity.

Figure 2

Figure 2

Forest plot of intrahepatic liver fat (IHL); SD, standard deviation; SMD, standard mean difference.

Figure 3

Figure 3

Forest plots of (A) alanine aminotransferase (ALT) in hypo-caloric group; (B) ALT in isocaloric group; (C) aspartate aminotransferase (AST) in hypocaloric group; (D) gamma-glutamyl transferase (γGT) in isocaloric group; SD, standard deviation; SMD, standardized mean difference.

Figure 4

Figure 4

Forest plots of (A) fasting glucose in isocaloric diet; (B) fasting insulin in isocaloric diet; (C) homeostatic model assessment for insulin resistance (HOMA-IR) in isocaloric diet; SD, standard deviation; SMD, standardized mean difference.

Figure 5

Figure 5

Forest plots of (A) total cholesterol (TC) in isocaloric diet; (B) low-density lipoprotein cholesterol (LDL-C) in isocaloric diet; (C) high-density lipoprotein cholesterol (HDL-C) in isocaloric diet; (D) triglycerides (TG) in isocaloric diet; SD, standard deviation; SMD, standardized mean difference.

References

    1. Younossi ZM, Koenig AB, Abdelatif D, Fazel Y, Henry L, Wymer M. Global epidemiology of nonalcoholic fatty liver disease-Meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology. (2016) 64:73–84. 10.1002/hep.28431 - DOI - PubMed
    1. Younossi Z, Tacke F, Arrese M, Chander Sharma B, Mostafa I, Bugianesi E, et al. Global perspectives on nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Hepatology. (2019) 69:2672–82. 10.1002/hep.30251 - DOI - PubMed
    1. Kim D, Kim WR. Nonobese fatty liver disease. Clin Gastroenterol Hepatol. (2017) 15:474–85. 10.1016/j.cgh.2016.08.028 - DOI - PubMed
    1. Puri P, Sanyal AJ. Nonalcoholic fatty liver disease: definitions, risk factors, and workup. Clin liver Dis. (2012) 1:99–103. 10.1002/cld.81 - DOI - PMC - PubMed
    1. Lonardo A, Ballestri S, Guaraldi G, Nascimbeni F, Romagnoli D, Zona S, et al. Fatty liver is associated with an increased risk of diabetes and cardiovascular disease - Evidence from three different disease models: NAFLD, HCV and HIV. World J Gastroenterol. (2016) 22:9674–93. 10.3748/wjg.v22.i44.9674 - DOI - PMC - PubMed

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