The anthropometric and metabolic impact of prebiotic, probiotics and synbioitcs for non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) patients; systematic review.

Abstract

Background and Aims: Although the global prevalence for non-alcoholic fatty liver disease (NAFLD) is reaching 20-30 % in high income countries, and the possibility of its progression into non-alcoholic steatohepatitis (NASH) there is yet no proven treatment other than lifestyle intervention. However, it has considerable limitations such as a questionable subjects’ commitment for an extended period, and it might not be suitable for individuals with normal body weight. There are multiple pieces of evidence postulated that the commensal bacteria in the gut microbiome (GM) play a role in NAFLD progression and development through the gut liver axis via the portal vein. Gut modifiers in terms of probiotics, prebiotics and synbiotics are materials that often aid these microorganisms to live and thrive. Therefore, the aim of the current paper is to systematically review the literature on the effect of these materials among these patients. This paper hypothesises that the supplementation of the gut modifiers may pose a protective outcome in terms of liver fat reduction, metabolic biomarkers, and anthropometric parameters improvement. Methods: Search was conducted in three databases for published studies with an open time frame using Scopus, EMBASE and PubMed. PICOS criteria for inclusion and exclusion was applied with a Boolean method that used “AND” and “OR”. The search was conducted from 27th May 2022 to 6th July 2022 by a single researcher (JSA) for the purpose of a master’s dissertation. EndNote X9.3.3 (Bld 15659) was used to manage the resources and aligned with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Results: Among 118 studies, only 17 studies met the inclusion criteria. Then, 4 were excluded because they did not assess liver fat as a primary outcome. Therefore, 13 studies from 8 countries were included in this paper. 7 studies investigated synbiotic, 5 studies experiment with probiotic and 1 study was on prebiotics. Some studies reported side effects after the intervention, while others did not report any. Discussion & Conclusion: It can be concluded that there is still not enough evidence in the literature to support their beneficial effects for NAFLD and NASH patients rather our knowledge is still in its infancy. Although this systematic review has considerable limitations such as it conducted by a single researcher and did not explore the unpublished records. Nonetheless, there is a potential for them as a treatment for NAFLD and NASH however further larger scale with prolonged duration, adequately designed with controlled confounders trails are required.