a Biotechnology Research Center , Mashhad University of Medical Sciences , Mashhad , Iran.
b Cardiovascular Research Center , Mashhad University of Medical Sciences , Mashhad , Iran.
Crit Rev Food Sci Nutr. 2017 Mar 4;57(4):666-676. doi: 10.1080/10408398.2014.948609.
In spite of promising experimental findings, randomized controlled trials (RCTs) have yielded mixed results on the impact of quercetin supplementation on plasma lipid levels.
The present study aimed to quantify the effects of quercetin on plasma lipids using a meta-analysis of RCTs.
A systematic literature search of Medline was conducted for RCTs that investigated the efficacy of quercetin supplementation on plasma lipids comprising total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid concentrations using a random-effects model. Meta-regression analysis was conducted to assess the effect of quercetin dose and duration of supplementation as moderators on the calculated effect measures.
Five RCTs totaling 442 subjects (221 in the quercetin and 221 in the control group) fulfilled the eligibility criteria and selected for analyses. Combined estimate of effect size for the impact of quercetin on plasma LDL-C (WMD: 1.43 mg/dL, 95% CI: -0.92-3.78, p = 0.23), HDL-C (WMD: 0.26 mg/dL, 95% CI: -0.74-1.25, p = 0.61) and triglycerides (WMD: -9.42 mg/dL, 95% CI: -27.80-8.96, p = 0.32) was not statistically significant. However, a borderline significant but clinically non-relevant increase in total cholesterol was observed (WMD: 3.13 mg/dL, 95% CI: -0.01-6.27, p = 0.05). When the analysis was confined to the subgroups of studies with quercetin doses ≥500 mg/day and follow-up of ≥ 4 weeks, a significant increase in total cholesterol (WMD: 3.57 mg/dL, 95% CI: 0.21-6.92, p = 0.04) and a decline in triglycerides (WMD: -24.54 mg/dL, 95% CI: -33.09 to -15.99, p < 0.00001) was observed, but LDL-C and HDL-C concentrations remained unchanged (p > 0.05). Changes in plasma triglycerides, but not other indices of lipid profile, were significantly associated with quercetin dose (slope: -0.057; 95% CI: -0.103 to -0.010; p = 0.02) and duration of supplementation (slope: -5.314; 95% CI: -9.482 to -1.147; p = 0.01).
Available evidence from RCTs does not suggest any clinically relevant effect of quercetin supplementation on plasma lipids, apart from a significant reduction of triglycerides at doses above 50 mg/day.
尽管有很有前景的实验结果，但随机对照试验（RCTs）在槲皮素补充对血浆脂质水平的影响方面得出的结果喜忧参半。
本研究旨在通过对 RCTs 的荟萃分析来量化槲皮素对血浆脂质的影响。
对 Medline 进行了系统的文献检索，以查找调查槲皮素补充对总胆固醇、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）和甘油三酯的血浆脂质疗效的 RCTs。使用随机效应模型计算脂质浓度净变化的加权均数差异（WMD）和 95%置信区间（CI）。进行了荟萃回归分析，以评估槲皮素剂量和补充持续时间作为调节因素对计算出的效应量的影响。
共有 5 项 RCT 符合纳入标准，共纳入 442 名受试者（槲皮素组 221 名，对照组 221 名）。槲皮素对 LDL-C（WMD：1.43mg/dL，95%CI：-0.92-3.78，p=0.23）、HDL-C（WMD：0.26mg/dL，95%CI：-0.74-1.25，p=0.61）和甘油三酯（WMD：-9.42mg/dL，95%CI：-27.80-8.96，p=0.32）的影响的综合效应大小估计没有统计学意义。然而，观察到总胆固醇的临界显著但临床无关的增加（WMD：3.13mg/dL，95%CI：0.01-6.27，p=0.05）。当分析仅限于槲皮素剂量≥500mg/天和随访时间≥4 周的研究亚组时，观察到总胆固醇（WMD：3.57mg/dL，95%CI：0.21-6.92，p=0.04）显著增加和甘油三酯（WMD：-24.54mg/dL，95%CI：-33.09 至-15.99，p<0.00001）下降，但 LDL-C 和 HDL-C 浓度保持不变（p>0.05）。血浆甘油三酯的变化，而不是其他血脂谱指标的变化，与槲皮素剂量（斜率：-0.057；95%CI：-0.103 至-0.010；p=0.02）和补充持续时间（斜率：-5.314；95%CI：-9.482 至-1.147；p=0.01）显著相关。
来自 RCTs 的现有证据表明，槲皮素补充除了在每天 50 毫克以上的剂量下可显著降低甘油三酯外，对血浆脂质没有任何临床相关的影响。
