Evidence related to a vegetarian diet and metabolic dysfunction-associated steatotic liver disease: protocol for a scoping review.

INTRODUCTION: Metabolic dysfunction-associated fatty liver disease (MASLD) is the hepatic manifestation of metabolic syndrome and the leading cause of chronic liver disease worldwide. Given that there is no pharmacological treatment for MASLD, it is imperative to understand whether lifestyle modifications may improve biochemical and pathological outcomes. One commonly proposed dietary modification is the Mediterranean diet; however, vegetarianism may also be a promising intervention. Vegetarianism has been shown to be associated with reduced morbidity and mortality in metabolic syndrome outcomes in coronary artery disease and diabetes; however, the relationship between vegetarian diet and MASLD is less clear. In this scoping review, we will provide a comprehensive overview of the current body of evidence related to a vegetarian diet and MASLD. METHODS AND ANALYSIS: The aim of this scoping review is to describe and summarise the current body of evidence related to MASLD and a vegetarian diet. This review will be conducted using Arksey and O'Malley's framework. The literature review will be conducted using the following databases: SCOPUS, Web of Science, CINAHL-Plus, Cochrane Library and Medline. No restriction will be made on publication date. Included studies will encompass clinical trials and observational designs that examine effects or association of vegetarian diet in adults (≥16 years) and report on the incidence, prevalence or progression of MASLD. Grey literature, non-human studies and articles focusing on changes in a specific food or nutraceutical will be excluded. Articles must have an English-language abstract available to be considered for inclusion. Screening and data extraction will be conducted by two independent reviewers. The findings will be summarised with descriptive statistics. ETHICS AND DISSEMINATION: Approval from a medical ethics committee is not required for this review. Once the review is complete, the findings will be submitted to a peer-reviewed journal.

Effects of n-3 fish oil on metabolic and histological parameters in NASH: a double-blind, randomized, placebo-controlled trial.

BACKGROUND & AIMS: This study's aim was to assess the histological and metabolic effects of n-3 polyunsaturated fatty acids (PUFAs) vs. placebo while adjusting for the impact of age and weight change in NASH patients. (ClinicalTrials.gov: NCT00681408). METHODS: Forty-one subjects with non-cirrhotic NASH were enrolled, and 34 completed the study. 17 received n-3 fish oil 3000 mg/day and 17 received placebo daily for 1 year with typical counselling on caloric intake and physical activity for all subjects. RESULTS: N-3- and placebo-treated groups showed no significant difference for the primary end point of NASH activity score (NAS) reduction ⩾ 2 points without fibrosis progression after adjustment for known covariates (n-3, 4/17 (23.5%); placebo, 3/17, (17.6%), p = 0.99). Among subjects with increased or stable weight, n-3 subjects showed a larger decrease in liver fat content by MRI than placebo-treated subjects (p = 0.014 for 2nd quartile, p = 0.003 for 3rd quartile of weight change). N-3 treatment showed significant fat reduction on the paired analysis of image-assisted fat morphometry regardless of weight loss or gain. Exercise capacity remained markedly reduced in all subjects. No independent effects on markers of hepatocyte injury or insulin sensitivity indices were observed. CONCLUSION: N-3 PUFAs at 3000 mg/day for one year did not lead to an improvement in the primary outcome of histological activity in NASH patients (⩾ 2 point NAS reduction). N-3 led to reduced liver fat by multiple measures. Other metabolic effects were not seen, although no detrimental effects were apparent. Whether longer duration, higher dose, or different composition of n-3 therapy would lead to additional benefits is uncertain.