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Green and Black Tea Consumption and Risk of Stroke

• Posted: 16 September 2009
• Categroy: Independent Research

Experimental models of stroke provide consistent evidence of smaller stroke volumes in animals ingesting tea components or tea extracts.

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 3 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 3 cups of tea per
day had a 21% lower risk of stroke than those consuming <1 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.

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