Effects of Nigella sativa on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials

Phytother Res. 2020 Oct;34(10):2586-2608. doi: 10.1002/ptr.6708. Epub 2020 May 11.

Abstract

The aim of this systematic review and meta-analysis was to evaluate the effects of Nigella sativa (N. sativa) on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress. Two independent authors systematically examined online databases consisting of, EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until October 30, 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of the studied trials. The heterogeneity among the included studies were assessed using the Cochrane's Q test and I-square (I2 ) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. A total of 50 trials were included in this meta-analysis. We found a significant reduction in total cholesterol (WMD: -16.80; 95% CI: -21.04, -12.55), triglycerides (WMD: -15.73; 95% CI: -20.77, -10.69), LDL-cholesterol (WMD: -18.45; 95% CI: -22.44, -14.94) and VLDL-cholesterol (WMD: -3.72; 95% CI: -7.27, -0.18) following supplementation with N. sativa. In addition, there was significant reductive effect observed with N. sativa on fasting glucose (WMD: -15.18; 95% CI: -19.82, -10.55) and HbA1C levels (WMD: -0.45; 95% CI: -0.66, -0.23). Effects of N. sativa on CRP (WMD: -3.61; 95% CI: -9.23, 2.01), TNF-α (WMD: -1.18; 95% CI: -3.23, 0.86), TAC (WMD: 0.31; 95% CI: 0.00, 0.63), and MDA levels (WMD: -0.95; 95% CI: -2.18, 0.27) were insignificant. This meta-analysis demonstrated the beneficial effects of N. sativa on fasting glucose, HbA1c, triglycerides, total-, VLDL-, LDL-cholesterol levels.

Keywords: HDL-cholesterol; LDL-cholesterol; Nigella sativa; insulin resistance; meta-analysis; oxidative stress.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Biomarkers / blood
  • Blood Glucose / drug effects*
  • Blood Glucose / metabolism
  • Cholesterol, LDL / blood
  • Dietary Supplements
  • Glycated Hemoglobin / drug effects
  • Glycated Hemoglobin / metabolism
  • Humans
  • Inflammation / blood
  • Inflammation / drug therapy*
  • Inflammation Mediators / blood
  • Insulin Resistance / physiology
  • Lipids / blood*
  • Nigella sativa / chemistry*
  • Nigella sativa / physiology
  • Oxidative Stress / drug effects*
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use*
  • Randomized Controlled Trials as Topic / statistics & numerical data
  • Triglycerides / blood

Substances

  • Biomarkers
  • Blood Glucose
  • Cholesterol, LDL
  • Glycated Hemoglobin A
  • Inflammation Mediators
  • Lipids
  • Plant Extracts
  • Triglycerides
  • hemoglobin A1c protein, human