The effects of nutritional interventions in patients with non-alcoholic fatty liver disease: An umbrella review of meta-analyses of randomized controlled trials

Background: Currently, there are no recognized interventions for the prevention and treatment of non-alcoholic fatty liver disease (NAFLD). Systematic reviews and meta-analyses of the relationship between nutritional interventions and NAFLD have yielded contradictory findings. Scope and approach: An umbrella review was conducted to assess the relationship between various nutritional intervention strategies and NAFLD. The AMSTAR 2 and GRADE were used to assess methodological quality and evidence quality. Key findings: The study examined 30 articles reporting 167 unique meta-analyses, covering 14 nutritional factors and 22 outcomes. In patients with NAFLD, moderate-quality evidence suggested that vitamin E supplementation decreased the steatosis score (WMD = -0.61, 95% CI: -0.89, -0.34), hepatocellular ballooning score (WMD = -0.32, 95% CI: -0.53, -0.10), and lobular inflammation score (WMD = -0.31, 95% CI: -0.52, -0.10). Supplementation of omega-3 polyunsaturated fatty acid (omega-3 PUFA) (RR = 1.52, 95% CI: 1.09, 2.13) and curcumin (RR = 3.96, 95% CI: 1.54, 10.17) presented greater improvement in liver steatosis in people with NAFLD, the quality evidence was moderate. In addition, moderate- to high-quality evidence showed that supplementation of vitamin D, vitamin E, omega-3 PUFA, probiotics, prebiotics, synbiotics, green tea exact, curcumin, Mediterranean diet, soy diet, and ginger improved anthropometric and biochemical indicators to some extent. Conclusion: Vitamin E, omega-3 PUFA, and curcumin have convinced evidence to improve the prognosis for patients with NAFLD. More studies are needed to explore the impact of vitamin D, probiotics, prebiotics, synbiotics, green tea exact, Mediterranean diet, soy diet, and ginger on NAFLD.