Effect of saffron supplementation on liver enzymes: a systematic review and meta-analysis of randomized controlled trials

Background and aims: Possible protective effects of saffron (Crocus sativus L) have been reported in several randomized clinical trials (RCTs). Current systematic review was performed to summarize the efficacy of saffron intake on liver enzymes. Methods: An electronic database search was conducted on PubMed/Medline, Scopus, Web of Science, and Cochrane for RCTs comparing effect of saffron and placebo on liver enzymes from inception to July 2021. There was no restriction in language of included studies and we calculated the standardized mean difference (SMD) and 95% Confidence Intervals (CI) for each variable. Random-effect model was used to calculate effect size. Results: Eight studies (n = 463 participants) were included in the systematic review. The saffron intake was associated with a statistically significant decrease in aspartate aminotransferase (AST) (SMD: -0.18; 95% CI: -0.34, -0.02; I-2 = 0%) in comparison to placebo intake. Our results also indicated that saffron consumption did not have a significant effect on alanine aminotransferase (ALT) (SMD: -0.14; 95% CI: -0.36, 0.09; I-2 = 47.0%) and alkaline phosphatase (ALP) levels (SMD: 0.14; 95% CI: -0.18, 0.46; I-2 = 42.9%) compared to placebo. Conclusions: Saffron intake showed beneficial impacts on circulating AST levels. However, larger well-designed RCTs are still needed to clarify the effect of saffron intake on these and other liver enzymes.