SCOPE: 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. METHODS AND RESULTS: 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. CONCLUSION: The present analysis suggests that flavonoid bioactivity does not follow a classical linear dose-response association and this may have important biological implications.
SCOPE: 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. METHODS AND RESULTS: 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. CONCLUSION: The present analysis suggests that flavonoid bioactivity does not follow a classical linear dose-response association and this may have important biological implications.
Authors: Mary Anne Nascimento-Souza; Pedro Gontijo de Paiva; Jara Pérez-Jiménez; Sylvia do Carmo Castro Franceschini; Andréia Queiroz Ribeiro Journal: Eur J Nutr Date: 2016-11-21 Impact factor: 5.614
Authors: Rishma Vidyasagar; Arno Greyling; Richard Draijer; Douglas R Corfield; Laura M Parkes Journal: J Cereb Blood Flow Metab Date: 2013-03-13 Impact factor: 6.200
Authors: Krishnaraj S Rathod; Daniel A Jones; T J A Van-Eijl; Hilda Tsang; Helen Warren; Stephen M Hamshere; Vikas Kapil; Ajay K Jain; Andrew Deaner; Neil Poulter; Mark J Caulfield; Anthony Mathur; Amrita Ahluwalia Journal: BMJ Open Date: 2016-12-20 Impact factor: 2.692