Nigella sativa (black seed) effects on plasma lipid concentrations in humans: A systematic review and meta-analysis of randomized placebo-controlled trials

Abstract

The effects of Nigella sativa (NS) on plasma lipid concentrations are controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to obtain a conclusive result in humans. PubMed-Medline, SCOPUS, Web of Science, and Google Scholar databases were searched (up to August 2015) to identify RCTs investigating the impact of NS on total cholesterol, LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), and triglycerides concentrations. A random-effects model and the generic inverse variance weighting method were used for quantitative data synthesis. Meta-regression, sensitivity analysis, and publication bias assessments were performed using standard methods. A total of 17 RCTs examining the effects of NS on plasma lipid concentrations were included. Meta-analysis suggested a significant association between NS supplementation and a reduction in total cholesterol (weighed-mean-difference [WMD]: -15.65mg/dL, 95% CI: -24.67, -6.63, p=0.001), LDL-C (WMD: -14.10mg/dL, 95% CI: -19.32, -8.88, p<0.001), and triglyceride levels (WMD: -20.64mg/dL, 95% CI: -30.29, -11.00, p<0.001). No significant effect on HDL-C concentrations (WMD: 0.28mg/dL, 95% CI: -1.96, 2.53, p=0.804) was found. A greater effect of NS seed oil versus seed powder was observed on serum total cholesterol and LDL-C levels, and an increase in HDL-C levels was found only after NS seed powder supplementation. NS has a significant impact on plasma lipid concentrations, leading to lower total cholesterol, LDL-C, and TG levels while increased HDL-C is associated with NS powder only. Further RCTs are needed to explore the NS benefits on cardiovascular outcomes.

Tiger nut oil-based diet improves the lipid profile and antioxidant status of male Wistar rats

“…These alterations suggest the importance of tiger nut oil‐based diet in the management or prevention of cardiovascular related disorder. This is consistent with previous studies demonstrating the importance of other seed and nut oil (Al‐Naqeep et al, ; Gossell‐Williams et al, ; Sahebkar et al, ). The elevated level of HDLc could lower predisposition to atherosclerosis and cardiovascular diseases (Chen et al, ).…”

Review on Clinical Trials of Black Seed (Nigella sativa ) and Its Active Constituent, Thymoquinone

“…Unlike pervasive evidence for the effects of NS use on the lipid profile, the administration of powdered NS seeds was reported to have had no significant effect on BP, serum lipid levels, blood sugar, or body weight in adults [73]. According to some meta-analyses, overall, the use of NS was shown to reduce the plasma levels of TC, LDL-C and TG, but its effect on HDL-C was not significant [74, 75]. Whereas the use of NS seed oil was observed to have greater effects on the serum TC and the LDL-C levels, versus the use of seed powder, elevation of the HDL-C levels was found only after supplementation with NS seed powder [75].…”

“…According to some meta-analyses, overall, the use of NS was shown to reduce the plasma levels of TC, LDL-C and TG, but its effect on HDL-C was not significant [74, 75]. Whereas the use of NS seed oil was observed to have greater effects on the serum TC and the LDL-C levels, versus the use of seed powder, elevation of the HDL-C levels was found only after supplementation with NS seed powder [75]. …”

Effect of Nigella sativa (black seed) supplementation on glycemic control: A systematic review and meta‐analysis of clinical trials

“…sativa powder (14.72 and 7.49, respectively) but on the contrary of FPG, powder had greater lowering effect on PPBG compared with oil (18.26 and 12.87, respectively). Other meta‐analysis that investigates different effect of oil and powder supplements also has been reported that oil supplement were more effective in lowering low‐density lipoprotein and cholesterol (Sahebkar, Beccuti, et al, ). However, N .…”