Effect of green coffee bean extract supplementation on liver function and inflammatory biomarkers: A meta-analysis of randomized clinical trials

Inflammation is considered a major contributor to non-alcoholic fatty liver disease (NAFLD) and several chronic diseases such as, cardiovascular disease and type two diabetes. Green coffee bean extract (GCBE) supplementation has been suggested to enhancing antioxidant capacity in people with obesity but results across studies are mixed. We conducted a meta-analysis of randomized controlled trials of GCBE supplementation in overweight/obese with normal liver function and NAFLD adults with ALT, AST, gamma-GTP, ALP, LDH, CRP, IL-6, and TNF-alpha as outcomes by searching PubMed and other databases. Eight studies were included, totaling 330 participants randomized to GCBE supplementation or placebo ranging from 50 mg/day to 1200 mg/day for 8-12 weeks. GCBE supplementation resulted in lower levels of TNF-alpha (mean difference = 1.37 pg/mL [95% CI = 0.97-1.76]; p < 0.00001). No significant difference was found in the remaining markers. In conclusion, GCBE supplementation attenuated TNF-alpha, a circulating inflammatory marker mediator which may be linked with lower systemic inflammation. However, potential cellular and molecular mechanisms by which GCBE exerts this positive effect warrants further investigations in human model studies.