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

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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 I2 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: −2.00, 1.52, P=0.788, respectively), but indirect comparison tests failed to significant differences between doses.

Conclusions: The results of the meta‐analysis showed a statistically significant effect of quercetin supplementation in the reduction of BP, possibly limited to, or greater with dosages of >500 mg/day. Further studies are necessary to investigate the clinical relevance of these results and the possibility of quercetin application as an add‐on to antihypertensive therapy.

No MeSH data available.


Funnel plot displaying publication bias in the studies reporting the impact of quercetin on systolic (upper plot) and diastolic (lower plot) blood pressure. The size of each circle is inversely proportional to the variance of change.
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jah31607-fig-0006: Funnel plot displaying publication bias in the studies reporting the impact of quercetin on systolic (upper plot) and diastolic (lower plot) blood pressure. The size of each circle is inversely proportional to the variance of change.

Mentions: Visual inspection of the funnel plot of SE versus effect size (mean difference) suggested a potential publication bias for the impact of quercetin on both SBP and DBP. Using trim‐and‐fill correction, 4 and 3 potentially missing studies were imputed for the analysis of SBP and DBP, respectively. The imputed effect sizes of quercetin on SBP and DBP were −4.51 mm Hg (95% CI: −6.55, −2.47; P<0.05) and −2.83 mm Hg (95% CI: −3.44, −2.22; P<0.05), respectively (Figure 6).


Effects of Quercetin on Blood Pressure: A Systematic Review and Meta ‐ Analysis of Randomized Controlled Trials
Funnel plot displaying publication bias in the studies reporting the impact of quercetin on systolic (upper plot) and diastolic (lower plot) blood pressure. The size of each circle is inversely proportional to the variance of change.
© Copyright Policy - creativeCommonsBy-nc
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015358&req=5

jah31607-fig-0006: Funnel plot displaying publication bias in the studies reporting the impact of quercetin on systolic (upper plot) and diastolic (lower plot) blood pressure. The size of each circle is inversely proportional to the variance of change.
Mentions: Visual inspection of the funnel plot of SE versus effect size (mean difference) suggested a potential publication bias for the impact of quercetin on both SBP and DBP. Using trim‐and‐fill correction, 4 and 3 potentially missing studies were imputed for the analysis of SBP and DBP, respectively. The imputed effect sizes of quercetin on SBP and DBP were −4.51 mm Hg (95% CI: −6.55, −2.47; P<0.05) and −2.83 mm Hg (95% CI: −3.44, −2.22; P<0.05), respectively (Figure 6).

View Article: PubMed Central - PubMed

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&#8208;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&#8208;controlled randomized controlled trials investigating the effect of quercetin on BP. Meta&#8208;analysis was performed using either a fixed&#8208;effects or random&#8208;effect model according to I2 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&#8208;analysis showed significant reductions both in systolic BP (WMD: &minus;3.04&nbsp;mm&nbsp;Hg, 95% CI: &minus;5.75, &minus;0.33, P=0.028) and diastolic BP (WMD: &minus;2.63&nbsp;mm&nbsp;Hg, 95% CI: &minus;3.26, &minus;2.01, P&lt;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&#8208;reducing effect in randomized controlled trials with doses &ge;500&nbsp;mg/day (WMD: &minus;4.45&nbsp;mm&nbsp;Hg, 95% CI: &minus;7.70, &minus;1.21, P=0.007 and &minus;2.98&nbsp;mm&nbsp;Hg, 95% CI: &minus;3.64, &minus;2.31, P&lt;0.001, respectively), and lack of a significant effect for doses &lt;500&nbsp;mg/day (WMD: &minus;1.59&nbsp;mm&nbsp;Hg, 95% CI: &minus;4.44, 1.25, P=0.273 and &minus;0.24&nbsp;mm&nbsp;Hg, 95% CI: &minus;2.00, 1.52, P=0.788, respectively), but indirect comparison tests failed to significant differences between doses.

Conclusions: The results of the meta&#8208;analysis showed a statistically significant effect of quercetin supplementation in the reduction of BP, possibly limited to, or greater with dosages of &gt;500&nbsp;mg/day. Further studies are necessary to investigate the clinical relevance of these results and the possibility of quercetin application as an add&#8208;on to antihypertensive therapy.

No MeSH data available.