The effect of Nigella sativa (black seed) on biomarkers of inflammation and oxidative stress: an updated systematic review and meta-analysis of randomized controlled trials

Objective This study was conducted to assess the effect of Nigella sativa (N. sativa) supplementation on inflammatory and oxidative markers among the adult population.Methods We carried out a comprehensive, systematic search of Scopus, Embase, Cochrane Library, Web of Science, PubMed, and Google Scholar till December 2022. A random-effects model was used to estimate the overall effect size.Results In total, twenty trials consisting of 1086 participants were included in the meta-analysis. Findings from 20 RCTs included in the meta-analysis suggest that N. sativa supplementation could significantly reduce serum C-reactive protein (CRP) (SMD = - 2.28; 95% CI - 3.20, - 1.37, p < 0.001), tumour necrosis factor a (TNFa) (SMD = - 1.21; 95% CI - 2.15, - 0.26; p = 0.013), and malondialdehyde (MDA) (SMD = - 2.15; 95% CI - 3.37, - 0.93, p < 0.001) levels, and significantly improves total antioxidant capacity (TAC) (SMD = 2.28; 95% CI 1.29, 3.27, p < 0.001), glutathione peroxidase (GPx) (SMD = 1.23, 95% CI 0.25, 2.22; p = 0.014) and superoxide dismutase (SOD) (SMD = 2.05; 95% CI 1.22, 2.88, p < 0.001) levels. However, no significant reduction was found in interleukin 6 (IL-6) levels (SMD = - 1.13; 95% CI - 2.72, 0.46, p = 0.162).Conclusion N. sativa supplementation had beneficial effects on CRP, TNF-a, MDA, SOD, GPx, and TAC. Thus, Nigella sativa can be recommended as an adjuvant anti-oxidant agent and anti-inflammatory.

Automated summary

This study aimed to evaluate the effect of Nigella sativa supplementation on inflammatory and oxidative markers among adults. The results of 20 randomized controlled trials showed that N. sativa supplementation significantly reduced serum CRP, TNF-a, and MDA levels, and significantly improved TAC, GPx, and SOD levels. However, there was no significant reduction in IL-6 levels. Therefore, Nigella sativa can be recommended as an adjuvant anti-oxidant agent and anti-inflammatory.