The effect of Nigella sativa on the measures of liver and kidney parameters: A systematic review and meta-analysis of randomized-controlled trials.

The aim of this systematic review and dose-response meta-analysis was to determine the effect of Nigella sativa (N.S) supplementation on liver and kidney parameters. We searched PubMed, Scopus, ISI Web of Science, Cochrane central register for controlled trials and Google Scholar from database inception to April 2019 for relevant controlled trials. Mean differences and standard deviations for each outcome were pooled using a random-effects model and a dose-response analysis was performed using a fractional polynomial model. Quality of evidence was evaluated using Cochrane Collaboration Risk of Bias tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Nineteen trials (n = 1295 participants) were included in the meta-analysis. We observed that N.S supplements had significant reducing effects on alkaline-phosphatase (ALP) [9 trials, n = 710 participants, weighted mean difference (WMD)= -10.825; 95 %CI: -19.658, -1.992 U/L; P = 0.016; I