title: 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.
authors.affiliation: Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Metabolic Research Centre, Royal Perth Hospital, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Sahebkar
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Beccuti
authors.affiliation: Biomedical Research Unit, Mexican Social Security Institute, Durango, Mexico.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Simental-Mendía
authors.affiliation: Hepato-Metabolic Disease Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Nobili
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy. Electronic address: simona.bo@unito.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Bo
mesh_terms: D000818:Animals; D006801:Humans; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D008055:Lipids / Q000097:blood; D031881:Nigella sativa / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic; D014280:Triglycerides / Q000097:blood
chemical_list: D002784:Cholesterol; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008055:Lipids; D010936:Plant Extracts; D014280:Triglycerides
keywords: Cholesterol; HDL-cholesterol; Nigella sativa; Triglycerides