The effect of nigella supplementation on blood pressure: A systematic review and dose-response meta-analysis

Abstract

This study was performed to assess the effect of nigella supplementation on blood pressure levels among the adult population. A comprehensive search was carried out through PubMed, Scopus, Web of Science, and Cochrane Library by using relevant keywords to find out the randomized clinical trials evaluating the effect of nigella administration on systolic blood pressure (SBP) and diastolic blood pressure (DBP). A random-effect model was applied to achieve the overall effect size. Subgroup analysis and meta-regression were used to explore the source of heterogeneity and the effects of the possible moderators. Of the twenty-two trials that were eligible for the present study, seventeen studies consisting of 1048 participants were included in the meta-analysis. The results indicated that nigella administration could significantly reduce both SBP (−4.58 mmHg; 95%CI: −6.22, −2.94) and DBP (−3.08 mmHg; 95%CI: −4.62, −1.55). Subgroup analysis did not show any superiority between subgroups of variables. Dose-response analysis detected a nonlinear association between dose and duration of administration and change in blood pressure outcomes, highlighting that maximum SBP and DBP reduction was experienced at 2000 mg/day and 8 weeks of nigella administration, respectively. The present study suggests that nigella supplementation can be beneficial for managing blood pressure.

Keywords:

• Nigella
• blood pressure
• hypertension
• meta-analysis

Authors’ contributions

M.P., A.H., S.G.-H., D.S., and A.N. carried out the conception and design of the study, acquisition of data, analysis, and interpretation of data; M.P., S.G.-H., and G.A., drafting the article or revising it critically for important intellectual content; M.P., and G.A., final approval of the version to be submitted. All authors have read and approved the final manuscript.

Disclosure statement

The authors report there are no competing interests to declare.

Data availability statement

The original contributions presented in the study are included in the article/Supplementary Materials. Further inquiries can be directed to the corresponding author.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.