Effects of 1 year combined flavan-3-ol and isoflavone intake, on biomarkers of vascular health in statin treated postmenopausal women with type 2 diabetes: a double-blind randomised controlled trial

Abstract

Type 2 diabetes (T2DM) increases cardiovascular disease (CVD) risk, adversely increasing common carotid artery intima-media thickness (CCA-IMT) (1) and endothelial dysfunction (2). Previously, higher intakes of some flavonoid sub-classes (specifically flavan-3-ols) have been associated with reduced atherosclerosis progression (3) , with animal and in vitro studies supporting benefits of this sub-class on Nitric Oxide (NO) (4) and NADPH oxidase activity (5) and of another sub-class, isoflavones, on vascular inflammation (6). The ability to metabolise the isoflavone equol, from its precursor, daidzein, has also been associated with improved vascular function (7). Despite these previous findings, the longer-term vascular effects of combined flavan-3-ol and isoflavone intakes remain under-studied and few studies have examined if these flavonoids augment standard therapies in controlling CVD risk in 'at-risk' populations, such as T2DM patients. In a randomised double-blind, parallel-design, placebo controlled study which was conducted in accordance with the Declaration of Helsinki guidelines, postmenopausal women with T2DM consumed 27 g/d (split-dose) flavonoid-enriched chocolate (850 mg flavan-3-ols (90 mg epicatechin) + 100 mg isoflavones (aglycone equivalents)/d), or matched placebo for 1-year. CCA-IMT, vascular biomarkers and measures of arterial stiffness (pulse wave velocity (PWV), augmentation Index (AIx)) and blood pressure (BP) were assessed. Changes from baseline (0 M) to 1-year (12M) were assessed with univariate ANCOVA. Flavonoid (n = 47) Placebo (n = 46) Net effect 0 to 12M p-value 0 to 12 M 0 M 0 to 12 M 0 M 0 to 12 M Mean SE Mean SE