Supplementary Material for: The Effect of Saffron Consumption on Liver Function: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

Background and Aims: The present systematic review and meta-analysis of randomized controlled trials aimed to determine the effects of saffron supplementation on liver function tests among adults. Methods: Electronic databases including PubMed, ISI Web of Science, and Scopus were searched up to January 2021. The risk of bias in individual studies was assessed using the Cochrane Collaboration tool. The overall estimates and their 95% CIs were calculated using random-effects models. Egger’s test and Begg’s rank-correlation were run to assess the presence of publication bias. p < 0.05 was considered statistically significant. Results: A total of 12 trials involving 608 participants were included in this systematic review and meta-analysis. Saffron supplementation had no significant effect on liver function tests including aspartate transaminase (AST) (weighted mean difference [WMD] = 0.23 U/L; 95% CI –2.22 to 2.69; p = 0.851; I2 = 74.0%), alanine aminotransferase (ALT) (WMD = –1.49 U/L; 95% CI –3.84 to 0.86; p = 0.213; I2 = 60.2%), and alkaline phosphatase (ALP) (WMD = –0.70 U/L; 95% CI –11.35 to 9.95; p = 0.898; I2 = 40.8%) compared to placebo. Conclusion: Based on what was discussed, it seems that saffron supplementation could not improve liver function tests including AST, ALT, and ALP among the adult population. Further clinical trials with larger sample size, longer duration, and higher doses of saffron should be conducted exclusively among patients with liver dysfunction to elucidate the beneficial role of saffron consumption on liver function.