Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK.
Mol Nutr Food Res. 2012 Nov;56(11):1605-16. doi: 10.1002/mnfr.201200363. Epub 2012 Sep 19.
Previous systematic reviews suggest beneficial effects of flavonoids on biomarkers of cardiovascular disease (CVD) risk, but have overlooked the impact of dose response or food complexity. The aim of the present study was to examine the relative impact of composition, flavonoid structure and dose.
MEDLINE, EMBASE and Cochrane were searched for randomised controlled trials (RCTs) of flavonoids or flavonoid-rich foods/extracts. Flavonoid composition was established using United States Department of Agriculture (USDA) and Phenol-Explorer databases. Effects of six flavonoid subgroups on endothelial function (flow-mediated dilation; FMD), and systolic and diastolic blood pressures were assessed by random effects meta-analyses and regression analyses. Meta-analyses of combined flavonoid subclasses showed significant improvements in FMD (chronic, 0.73% (0.17, 1.30) 14 RCTs; acute, 2.33% (1.58, 3.08) 18 RCTs) and blood pressures (systolic, -1.46 mmHg (-2.38, -0.53) 63 RCTs; diastolic, -1.25 mmHg (-1.82, -0.67) 63 RCTs). Similar benefits were observed for the flavan-3-ol, catechol flavonoids (catechins, quercetin, cyanidin etc.), procyanidins, epicatechin and catechin subgroups. Dose-response relationships were non-linear for FMD (R(2) ≤ 0.30), with greater associations observed when applying polynomial regression analyses (R(2) ≤ 0.72); there was no indication of a dose response for blood pressure.
The present analysis suggests that flavonoid bioactivity does not follow a classical linear dose-response association and this may have important biological implications.
先前的系统评价表明，类黄酮对心血管疾病（CVD）风险的生物标志物有有益影响，但忽略了剂量反应或食物复杂性的影响。本研究的目的是检查组成、类黄酮结构和剂量的相对影响。
通过 MEDLINE、EMBASE 和 Cochrane 搜索了关于类黄酮或富含类黄酮的食物/提取物的随机对照试验（RCT）。使用美国农业部（USDA）和 Phenol-Explorer 数据库确定类黄酮的组成。通过随机效应荟萃分析和回归分析评估了六个类黄酮亚组对内皮功能（血流介导的扩张；FMD）和收缩压和舒张压的影响。联合类黄酮亚组的荟萃分析显示，FMD（慢性，0.73%（0.17，1.30）14 项 RCT；急性，2.33%（1.58，3.08）18 项 RCT）和血压（收缩压，-1.46 mmHg（-2.38，-0.53）63 项 RCT；舒张压，-1.25 mmHg（-1.82，-0.67）63 项 RCT）有显著改善。在黄烷-3-醇、儿茶素类黄酮（儿茶素、槲皮素、矢车菊素等）、原花青素、表儿茶素和儿茶素亚组中也观察到了类似的益处。FMD 的剂量-反应关系是非线性的（R²≤0.30），当应用多项式回归分析时，观察到更大的相关性（R²≤0.72）；血压没有显示出剂量反应的迹象。
本分析表明，类黄酮的生物活性不遵循经典的线性剂量-反应关联，这可能具有重要的生物学意义。
