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Effects of Quercetin on Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Serban MC, Sahebkar A, Zanchetti A, Mikhailidis DP, Howard G, Antal D, Andrica F, Ahmed A et al.

Journal of the American Heart Association, 2016

587 participants · 313 citations

Abstract

BACKGROUND: Quercetin, the most abundant dietary flavonol, has antioxidant effects in cardiovascular disease, but the evidence regarding its effects on blood pressure (BP) has not been conclusive. We assessed the impact of quercetin on BP through a systematic review and meta-analysis of available randomized controlled trials.

METHODS AND RESULTS: We searched PUBMED, Cochrane Library, Scopus, and EMBASE up to January 31, 2015 to identify placebo-controlled randomized controlled trials investigating the effect of quercetin on BP. Meta-analysis was performed using either a fixed-effects or random-effect model according to I(2) statistic. Effect size was expressed as weighted mean difference (WMD) and 95% CI. Overall, the impact of quercetin on BP was reported in 7 trials comprising 9 treatment arms (587 patients). The results of the meta-analysis showed significant reductions both in systolic BP (WMD: -3.04 mm Hg, 95% CI: -5.75, -0.33, P=0.028) and diastolic BP (WMD: -2.63 mm Hg, 95% CI: -3.26, -2.01, P<0.001) following supplementation with quercetin. When the studies were categorized according to the quercetin dose, there was a significant systolic BP and diastolic BP-reducing effect in randomized controlled trials with doses ≥500 mg/day (WMD: -4.45 mm Hg, 95% CI: -7.70, -1.21, P=0.007 and -2.98 mm Hg, 95% CI: -3.64, -2.31, P<0.001, respectively), and lack of a significant effect for doses <500 mg/day (WMD: -1.59 mm Hg, 95% CI: -4.44, 1.25, P=0.273 and -0.24 mm Hg, 95% CI:…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 587 participants or records.

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