Effects of green coffee extract supplementation on glycemic indexes, leptin, and obesity values in patients with non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity and type 2 diabetes. This study aimed to investigate the effects of green coffee extract (GCE) on glycemic indexes, leptin levels, and obesity values in patients with NAFLD. This double-blind, randomized, controlled clinical trial was conducted on 48 patients with NAFLD aged 20-60 years and body mass index (BMI) of 25-35 kg/m(2). Subjects were randomly assigned to receive a daily dose of 400 mg GCE (2 x 300 mg; n = 24) or placebo (n = 24) for eight weeks. Fasting blood samples, anthropometric measurements, and dietary intake data was collected for all patients at baseline and at the end of the study. GCE supplementation significantly reduced fasting blood glucose (mean difference (MD) = -11.50 and 95 % confidence interval (CI) = -19.59 to -3.42), homeostatic model assessment for insulin resistance (MD = -0.97 and 95 % CI = -1.84 to -0.11), weight (MD = -1.73 and 95 % CI = -2.44 to -1.01), BMI (MD = -0.57 and 95 % CI = -0.84 to -0.29), and waist circumference (MD = -3.69 and 95 % CI = -5.85 to -1.54) in the intervention group compared to the control group. Serum leptin levels decreased significantly in GCE group compared to the baseline values (P = 0.022). No significant changes were observed in serum insulin concentration and waist to hip ratio in any of the groups. In conclusion, GCE supplementation improved glycemic parameters and obesity values and may be useful in the management of NAFLD complications.