The Effects of Nigella sativa Supplementation on Liver Enzymes Levels: a Systematic Review and Meta-analysis of Randomized Controlled Trials.

The present systematic review and meta-analysis aimed to investigate the effects of Nigella sativa (N. sativa) supplementation on liver enzymes levels including aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Relevant studies, published from inception up to January 2020, were searched through PubMed, Scopus and Google Scholar conducted on randomized controlled trials (RCTs) investigating the effect of N. sativa on serum AST and ALT levels. Meta-analysis was applied using a random-effects model. Eight studies met inclusion criteria (n=281 in the N. sativa and n = 279 in placebo group). This meta-analysis showed that N. sativa supplementation significantly reduced AST level (weighted mean difference [WMD], -8.11 IU/L; 95% confidence interval [CI], -13.6, -2.53; p = 0.004) with significant heterogeneity (I-squared, 95.9%; p < 0.001) while the decrease in ALT level was not statistically significant (WMD, -7.26 IU/L; 95% CI, -15.4, 0.04; p = 0.051) with significant heterogeneity (I-squared, 97.8%; p < 0.001). This meta-analysis suggests that N. sativa supplementation may improve AST levels and ALT levels, however more RCTs with larger sample size are needed to found effects of N. sativa on liver enzymes in patients with non-alcoholic fatty liver disease.