Both black and green tea consumption associated with reduced risk of stroke

Animal experiments show tea extracts to reduce the infarct volume in a dose dependent fashion. To examine whether tea consumption in man is associated with a reduced risk of cerebral infarction in man we conducted a research librarian supported literature search and a meta analysis of all published human clinical and epidemiologic research on tea and stroke. Risk estimates in each study were calibrated to estimate the effect on stroke associated with consumption of 3 cups of tea. Of 59 citations, 10 studies were identified with original data on either fatal or non‐fatal ischemic stroke in relationship to tea consumption. All of these studies provided risk point estimates below 1.0. The meta analysis demonstrated no significant heterogeneity across studies. The pooled, fixed effect relative risk was 0.79 with a 95% confidence interval of 0.73‐0.85. These effects were quite consistent for black tea (RR=0.76, 0.67‐0.86) and green tea (RR=0.79, 0.72‐0.86). We found that, regardless of country of origin or type of tea consumed, the additional consumption of 3 cups of tea per day is associated with an average 21% lower risk of ischemic stroke, suggesting that the onset of ischemic stroke in man may be prevented through daily tea consumption.