Regular Consumption of Green Tea Associated with Cardiovascular Protective Effects

by | Jul 7, 2020 | 2019, Blood Pressure, Cardiovascular Health

Written by Angeline A. De Leon, Staff Writer. Study finds that regular consumption of green tea improves pulse pressure and induces regression of left ventricular hypertrophy in hypertensive patients.

teaHypertension, defined as blood pressure above 140/90, has been linked to clinical complications such as retinopathy and nephropathy, but is perhaps best known as a risk factor for cardiovascular disease (CVD) (1, 2). A growing body of research suggests that pulse pressure (PP, the difference between systolic blood pressure [SBP] and diastolic blood pressure [DBP]) may be an independent and more accurate predictor of CVD, particularly for middle-aged and older adults (3, 4). This may be true even for individuals with normal blood pressure levels (5). According to a number of animal studies, regular consumption of green tea appears to exert a hypotensive effect (6, 7). In rats with cardiac hypertrophy, for example, green tea has been shown to effectively attenuate left ventricle hypertrophy (LVH, referring to the thickening and enlargement of the left ventricle) (8). In human subjects, however, the impact of long-term green tea intake on blood pressure is associated with more variable results (9). To this end, a 2019 study published in Physiological Reports endeavored to conduct the first investigation to examine the effects of regular green tea consumption on PP and LVH in patients with hypertension.

A total of 200 patients (mean age = 53 +/- 4 years) with hypertension (SBP of 150-180 mmHg and/or DBP of 95-120 mmHg) were enrolled in a randomized, placebo-controlled trial. For the first 4 months, participants were randomly assigned to drink 250 mL of either green tea (containing about 130 mg of flavonoids) (Group 1) or hot water (Group 2). Subjects then switched to the second arm of the study and completed the alternate protocol for an additional 4 months. At baseline and at the end of each month of intervention, SBP, DBP, PP, and heart rate (HR) were measured. Electrocardiograms (ECGs) and echocardiography were also performed at the beginning and end of each intervention period to determine LVH.

At the end of 4 months, green tea supplementation in Group 1 was associated with a significant decrease in SBP (-6.6%, p < 0.001), DBP (-5.1%, p < 0.01), and PP (-9.1%, p < 0.05). In Group 2, intake of hot water did not significantly change blood pressure values from baseline to Month 4, however, supplementation with green tea during the second treatment phase was shown to significantly lower SBP (-5.4%, p < 0.001), DBP (-4.1%, p < 0.05), and PP (-7.7%, p < 0.05). At baseline, 20% of subjects in Group 1 and 24% of subjects in Group 2 showed evidence of LVH based on ECG and echocardiography. However, after 4 months of green tea consumption, LVH rates significantly decreased to 8% for Group 1 and 10% for Group 2 (p < 0.01 for both).

The present study provides initial evidence for the cardioprotective benefits of green tea on PP and LVH in hypertensive patients. Consumption of four standard cups of green tea on a daily basis was associated with significant improvement of SBP, DBP, and PP over the course of 4 months. For both study groups, the incidence of LVH also significantly diminished with green tea supplementation, further confirming the hypotensive effects of green tea. Although the exact mechanisms associated with green tea’s attenuation of hypertension are still being studied, the present trial suggests that chronic intake of green tea has clear cardioprotective benefits. Potential study limitations relate to the continuation of subjects’ anti-hypertensive therapy programs during the course of the study and the observed differences in treatment adherence between subjects in Group 1 and Group 2.

Source: Al-Shafei AIM, El-Gendy OAA. Regular consumption of green tea improves pulse pressure and induces regression of left ventricular hypertrophy in hypertensive patients. Physiological Reports. 2019; 7(6): e14030. DOI: 10.14814/ph2.14030

© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Click here to read the full text study.

Posted July 7, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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