Coffee Consumption and the Progression of NAFLD: A Systematic Review

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in developed countries. Coffee is one of the most consumed beverages in the world and has been shown to be beneficial in limiting progression in chronic liver disease in general. However, research surrounding the impact of coffee consumption on NAFLD progression is limited. This systematic review aimed to investigate the relationship between coffee consumption and the progression of liver disease, specifically for cases of NAFLD. MEDLINE, EMBASE, CINAHL, the Cochrane Library, and Scopus were searched for published studies that evaluated the effects of coffee consumption on the progression of NAFLD. The results are presented in a narrative synthesis with principal summary measures, including odds ratios, p-values, and differences in mean coffee intake in relation to severity of NAFLD. Five studies met the inclusion criteria and were included in this review. There was no trial evidence among NAFLD patients, rather all studies were of a cross-sectional design. Using the Academy of Nutrition and Dietetics Quality Criteria Checklist, four studies received a positive rating, with the remaining study receiving a neutral rating. Overall, four out of the five studies reported a statistically significant relationship between coffee consumption and the severity of fibrosis. Methods around capturing and defining coffee consumption were heterogeneous and therefore an effective dose could not be elucidated. Results suggest that higher coffee consumption is inversely associated with the severity of hepatic fibrosis in individuals with NAFLD. However, further research is required to elucidate the optimum quantity and form/preparation of coffee required to exert this hepatoprotective role.