Polyphenols in grape and wine have been suggested to contribute to the cardiovascular health benefits of the Mediterranean lifestyle. The reported effects of grape products on blood pressure (BP) remain, however, equivocal. In a double-blind placebo controlled crossover study, the effect of two grape extracts on BP and vascular function was assessed in 60 untreated, mildly hypertensive subjects after four weeks intervention. Both extracts (grape-red wine and grape alone) had high concentrations of anthocyanins and flavonols, but the grape alone was relatively poor in catechins and procyanidins. Parameters measured included ambulatory and office BP, flow-mediated vasodilation, arterial distensibility, platelet function and plasma lipoproteins. Results showed that 24-hour ambulatory systolic/diastolic BPs were significantly lower in the grape-wine extract intervention (135.9 ± 1.3/84.7 ± 0.8 mmHg; mean ± SEM) compared to placebo (138.9 ± 1.3/86.6 ± 1.2 mmHg), predominantly during daytime. Plasma concentrations of the vasoconstrictor endothelin-1 decreased by 10%, but other measures of vascular function were not affected. Grape juice extract alone had no effect on BP or any measures of vascular function. Polyphenol-rich food products, and may be specifically catechins and procyanidins, may thus help sustain a healthy BP and contribute to the healthy Mediterranean lifestyle.

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examine the effect of acute black tea ingestion on cutaneous microvascular function. 5Methods. Twenty healthy participants (58±5 yr, 9 men) attended two experimental 6 trials (tea, placebo), 7-days apart in a randomised, controlled, double-blind, cross-over 7 design. Participants ingested a single dose of 200ml black tea or placebo, followed by 8 assessment of forearm cutaneous perfusion using laser-Doppler flowmetry (LDF) 9 using three distinct heating protocols, enabling us to distinguish between axon-and 10 endothelium-dependent vasodilation: 1. rapid 42°C, 2. rapid 39°C and 3. gradual 42°C. 11On the contralateral arm, full-field laser perfusion imaging (FLPI) was used to assess Results. Rapid local heating to 39°C or 42°C demonstrated no effect of tea for flux, 16CVC or %CVCmax (all P>0.05). Gradual local heating to 42°C, however, produced a

Beneficial effects of flavonoid-rich black and green tea on macrocirculation have been well established. Theaflavins are unique to black tea as they are formed from catechins during the enzymatic oxidation of tea leaves. The study was performed to gain more insight into the effects of theaflavins on microcirculation and to compare effects with another important flavonoid class, the green tea derived catechins, which have been reported to improve vascular function. Twenty-four healthy subjects were included in a double-blind, placebo-controlled, randomised, cross-over study. On six different days, subjects received capsules with a single dose of catechins (500 mg), four varying doses of theaflavins (100 to 500 mg) or placebo. Microcirculation was assessed after each treatment by Pulse Amplitude Tonometry (EndoPAT) at baseline and 2, 4 and 6 h after test product intake. The EndoPAT reactive hyperemia response was improved by 500 mg catechins (reactive hyperemia index (RHI): 0.2; p = 0.04) and by 500 mg theaflavins (RHI: 0.19; p = 0.06) compared to placebo. Also, 300 mg theaflavins increased the RHI (0.28; p = 0.02), but no effects were observed at lower doses. The study suggests moderate effects of single doses of catechins and theaflavins on peripheral microcirculation.

Purpose The aim of this study was to examine if catechin‐rich green tea abrogates the negative effects of 7‐days of physical inactivity and excessive calorie‐intake on insulin homeostasis and peripheral vascular function. Methods Using a randomized, double‐blind, crossover design, twelve healthy men (29 ± 6 yrs) underwent 7‐days unhealthy lifestyle (UL), including physical inactivity (−50% steps/day) and overfeeding (+50% kcal/day). This was combined with green tea consumption (UL‐tea; 3 doses/day) or placebo (UL‐placebo). Before and after each intervention, we examined postprandial blood glucose and insulin (3‐h after a 1,202 kcal meal) and upper and lower limb vascular function (flow‐mediated dilation (FMD%)) and carotid artery reactivity (CAR%). Results UL‐placebo increased postprandial glucose and insulin, while UL‐tea decreased postprandial glucose and insulin (Time*Intervention interaction effects: both p < 0.05). UL‐placebo decreased CAR% and femoral FMD%, while UL‐tea prevented these effects (Time*Intervention interaction effects of p < 0.04 and p < 0.001, respectively). There was no main effect of Time or Time*Intervention interaction (both p > 0.05) for brachial FMD%. Conclusion Seven days of physical inactivity and overfeeding impair insulin homeostasis and vascular function. These effects were mitigated by a daily intake of catechin‐rich green tea.

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