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

Pharmacol Res. 2016 Apr;106:37-50. doi: 10.1016/j.phrs.2016.02.008. Epub 2016 Feb 10.

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.

Keywords: Cholesterol; HDL-cholesterol; Nigella sativa; Triglycerides.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Animals
  • Cholesterol / blood
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Humans
  • Lipids / blood*
  • Meta-Analysis as Topic
  • Nigella sativa / chemistry*
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use*
  • Randomized Controlled Trials as Topic
  • Triglycerides / blood

Substances

  • Cholesterol, HDL
  • Cholesterol, LDL
  • Lipids
  • Plant Extracts
  • Triglycerides
  • Cholesterol