Flavonoid-rich fruit and vegetables improve microvascular reactivity and inflammatory status in men at risk of cardiovascular disease—FLAVURS: a randomized controlled trial

ABSTRACT Background – Observed associations between increased fruit and vegetable (F&V) consumption, particularly those rich in flavonoids, and vascular health improvements, require confirmation in randomised controlled trials. This study was designed to measure the dose-response relationship between high- vs low-flavonoid vs habitual F&V intake, vascular function and other cardiovascular disease (CVD) risk indicators. Method and Results – A single-blind, dose-dependent, parallel, randomised, controlled dietary intervention study was conducted. Low F&V consumers who had ≥1.5 fold increased risk of CVD (n=174) were randomly assigned to high-flavonoid (HF), low-flavonoid (LF) or habitual diet (CT), with HF and LF F&V portion numbers sequentially increasing by 2, 4 and 6 portions/day every 6wk in the HF and LF groups respectively over their habitual intake. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness and tone (Pulse Wave Velocity/Analysis), blood pressure, biomarkers of nitric oxide (NO), vascular function and inflammation were determined at baseline, 6, 12 and 18wk. In men HF F&V increased endothelium-dependent microvascular reactivity (P=0.017), (additional 2.5 portions); reduced C-reactive protein (P=0.001), E-Selectin (P=0.0005) and vascular cell adhesion molecule (P=0.0468) (additional 3 portions), and HF F & V raised plasma NO (P=0.0243) (additional 3 portions) in the group as whole. An increase in F&V, irrespective of flavonoid content, attenuated reduction in vascular tone (P=0.0065) and NO (P=0.0299) in the CT. Conclusions – Consumption of ≥6 portions of F&V, particularly those rich in flavonoids, was associated with an increase in endothelium-dependent microvascular function and a reduction in inflammation status in men at risk from CVD.