The Association between Coffee Consumption and Non-Alcoholic Fatty Liver Disease: Is there a Protective Role?

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease. Several studies have suggested a protective role of coffee in chronic liver disease, but their results remain controversial. AIM: The purpose of the study was to investigate the association between coffee consumption and the prevalence and severity of NAFLD in a non-diabetic and non-alcoholic population. METHODS: This study involved 157 participants. Cases were defined by the presence of steatosis on liver ultrasound, the severity of which was assessed by the Bright Liver Steatosis Score. Controls were defined by the absence of steatosis on liver ultrasound. All patients with cytolysis and/or cholestasis had an etiological investigation (serologic testing for Hepatitis B virus and hepatitis C virus infection, and autoimmune investigation). All participants underwent liver ultrasound, clinical assessment (blood pressure, waist circumference, and body mass index (BMI)), and biological assessment (Complete Blood Count, lipid profile test, liver function tests, and Fasting Blood Glucose [FBG]). Dietary assessment was conducted using a food frequency questionnaire, coffee consumption was dichotomized into present or absent and then categorized according to the number of cups consumed per day. RESULTS: The study included 94 NAFLD and 63 controls, the two groups were comparable in demographic characteristics. The means of systolic blood pressure, BMI, waist circumference, Aspartate Transaminase, Alanine Transaminase (ALT), Gamma-Glutamyl transferase (GGT), alkaline phosphatase, and FBG were significantly higher in the NAFLD group. The study of the association between coffee consumption and NAFLD showed a significant decrease in the risk of its occurrence (Odds Ratios [OR] = 0.39) and its severity (OR = 0.32) in coffee consumers, mainly in those consuming 3 or more cups. In multivariate analysis, the following factors were associated with increased prevalence of NAFLD: Metabolic syndrome, high mean levels of alkaline phosphatase, GGT, ALT, FBG, BMI, and waist circumference. However, Green tea consumption was not associated with either prevalence or severity of NAFLD (OR = 1.02, p = 0.82). CONCLUSION: Coffee consumption is inversely associated with the prevalence and severity of NAFLD. Further prospective studies are needed to establish a cause-effect relationship between coffee and NAFLD.