The effect of probiotic consumption on lipid profile, glycemic index, inflammatory markers, and liver function in NAFLD patients: A systematic review and meta-analysis of randomized controlled trials

Background-aim: Non-alcoholic fatty liver disease (NAFLD 1 ) is the most frequent chronic liver disorder worldwide. Currently, no pharmacological treatment has been approved for NAFLD. Probiotics have been suggested as a potential therapy for NAFLD. The aim of this systematic review and meta-analysis was to assess the impact of probiotic intake on liver tests, lipids, glycemic parameters and inflammatory markers in NAFLD patients. Methods: We searched electronic databases using related terms. Meta-analysis was performed using randomeffects models. Clinical outcomes were presented as standard mean difference (SMD 2 ) with a 95 % confidence interval (CI 3 ). Publication bias and heterogeneity were evaluated in eligible studies. Results: Fifteen randomized clinical trials comprising 899 participants were included in our meta-analysis. Probiotic supplementation improved alanine transaminase [SMD-0.796; 95 % CI (-1.419,-0.172); p = 0.012], Homeostatic Model Assessment for Insulin Resistance (HOMA-IR 4 ) [SMD-0.596; 95 % CI (-1.071,-0.121); p = 0.01] and insulin levels [SMD-1.10; 95 % CI (-2.121,-0.087); p = 0.03]. No significant effects were observed on fasting glucose, hemoglobin A1c, aspartate transaminase, lipid profile, interleukin-6 and tumor necrosis factor- alpha. Conclusions: Probiotic intake may improve insulin sensitivity and alanine transaminase in NAFLD patients.