Black tea lowers blood pressure and wave reflections in fasted and postprandial conditions in hypertensive patients: a randomised study.

Davide Grassi,Giovambattista Desideri,Theo Mulder,Claudio Ferri,Richard Draijer

doi:10.3390/nu7021037

Abstract

Hypertension and arterial stiffening are independent predictors of cardiovascular mortality. Flavonoids may exert some vascular protection. We investigated the effects of black tea on blood pressure (BP) and wave reflections before and after fat load in hypertensives. According to a randomized, double-blind, controlled, cross-over design, 19 patients were assigned to consume black tea (129 mg flavonoids) or placebo twice a day for eight days (13 day wash-out period). Digital volume pulse and BP were measured before and 1, 2, 3 and 4 h after tea consumption. Measurements were performed in a fasted state and after a fat load. Compared to placebo, reflection index and stiffness index decreased after tea consumption (p < 0.0001). Fat challenge increased wave reflection, which was counteracted by tea consumption (p < 0.0001). Black tea decreased systolic and diastolic BP (−3.2 mmHg, p < 0.005 and −2.6 mmHg, p < 0.0001; respectively) and prevented BP increase after a fat load (p < 0.0001). Black tea consumption lowers wave reflections and BP in the fasting state, and during the challenging haemodynamic conditions after a fat load in hypertensives. Considering lipemia-induced impairment of arterial function may occur frequently during the day, our findings suggest regular consumption of black tea may be relevant for cardiovascular protection.

Highlights

Hypertension is the leading risk factor for cardiovascular morbidity and mortality [1]
The novel finding of this study is that consumption of black tea, naturally rich in flavonoids, compared to a surrogate placebo resulted in significantly lower wave reflections and blood pressure (BP)
We showed decreased peripheral vascular tone and wave reflections, suggesting that tea consumption caused vasodilation of peripheral arteries indicating a decrease of vascular resistance, offering a putative mechanism for the reported effects in reducing BP

Summary

Introduction

Hypertension is the leading risk factor for cardiovascular morbidity and mortality [1]. Increased peripheral resistance due primarily to changes in vascular structure and function appear to be the fundamental hemodynamic abnormality in hypertension [2] These changes include endothelial dysfunction, arterial wall thickening and abnormal vascular tone, and are due to alterations in the biology of the arterial wall [2]. Aortic stiffening and arteriolar remodeling due to hypertension augment the central pressure by increasing the wave reflection but may alter the central bidirectional flow, inducing hemodynamic damage/dysfunction in target organs. An increasing number of studies have indicated arterial stiffness and the amount of pulse wave reflections as independent predictors of cardiovascular events and cardiovascular mortality in patients with different co-morbidities and cardiovascular risk [3,4,5].

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