Green and Black Tea Consumption and Risk of Stroke

Abstract

Background and Purpose-Experimental models of stroke provide consistent evidence of smaller stroke volumes in animals ingesting tea components or tea extracts. To assess whether a similar association of black or green tea consumption with reduced risk is evident in human populations, we sought to identify and summarize all human clinical and observational data on tea and stroke. Methods-We searched PubMed and Web of Science for all studies on stroke and tea consumption in humans with original data, including estimation or measurement of tea consumption and outcomes of fatal or nonfatal stroke. Data from 9 studies involving 4378 strokes among 194 965 individuals were pooled. The main outcome was the occurrence of fatal or nonfatal stroke. We tested for heterogeneity and calculated the summary effect estimate associated with consumption of Ն3 cups of tea (green or black) per day using random-effects and fixed-effects models for the homogeneous studies. Publication bias was also evaluated. Results-Regardless of their country of origin, individuals consuming Ն3 cups of tea per day had a 21% lower risk of stroke than those consuming Ͻ1 cup per day (absolute risk reduction, 0.79; CI, 0.73 to 0.85). The proportion of heterogeneity not explained by chance alone was 23.8%. Conclusions-Although a randomized clinical trial would be necessary to confirm the effect, this meta-analysis suggests that daily consumption of either green or black tea equaling 3 cups per day could prevent the onset of ischemic stroke.

Cancer Chemoprevention by Dietary Polyphenols

“…It has been found that green tea consumption is significantly associated with a lower risk of mortality due to stroke [29] and pneumonia [30] and imparts a lower risk of cognitive impairment [31], depression [32], and psychological distress [33]. These results have been confirmed by other researchers [34][35][36][37]. In addition, other epidemiologic studies have indicated that green tea consumption is associated with a lower risk of osteoporosis [38,39], and randomized placebo-controlled trials have indicated that green tea is effective in lowering cardiovascular risk factors [40,41].…”

Tea Consumption and Longitudinal Change in High‐Density Lipoprotein Cholesterol Concentration in Chinese Adults

“…In 2016, 17.6 million deaths were caused by CVD; the death from cardiovascular diseases increased by 14.5% from 2006 and 2016 1. Previous epidemiological studies suggest that greater tea consumption is related to lower cardiovascular disease (CVD) risk2, 3; 1 to 3 or more cups of green or black tea per day is associated with a 20% to 30% risk reduction in stroke and CVD 3, 4. Produced from Camellia sinensis and rich in polyphenols and catechins, green and black tea were reported to exert a cardioprotective effect via antioxidation of proteins, DNAs, and lipids; antiproliferation of vascular smooth muscle cell; anti‐inflammation in cardiovascular cells; and improvement in endothelial functions, blood pressure,5 and lipid profile 6…”

Association of flavonoid-rich foods and flavonoids with risk of all-cause mortality

“…Meta-analyses have shown that consumption of flavonoid-rich foods are associated with reduced 28 risk of cause-specific mortalities such as those attributable to cancer, diabetes, and 29 cardiovascular disease [4][5][6][7] . Much of the beneficial effects of these foods have been attributed to 30 their high content of biologically active flavonoids, which have been shown to improve nitric 31 oxide homeostasis and endothelial function, and reduce platelet aggregation and oxidative 32 stress [8][9][10][11][12][13] .…”