Review: Drinking tea and the risk of stroke

 Drinking at least 3 cups of black or green tea was associated with a 21% lower risk of stroke compared to consuming less than a cup a day, report researchers at the University of California, Los Angeles.

The results were presented during the American Stroke Association International Stroke Conference.

First, the details.

  • Data were combined and a meta-analysis conducted on studies of 4,378 strokes in 194,965 individuals.
  • 7 studies included those who drank primarily or exclusively black tea.
  • 3 groups consumed primarily green tea.

And, the results.

  • 5 studies produced nonsignificant relationships between tea intake and stroke.
  • But, when pooled, the evidence was consistent despite different drinking customs and a broad range of risks for death due to stroke, across the 6 countries.
  • Drinking at least 3 cups of tea per day was associated with a significant 21% lower risk of stroke.
  • Except for 1 study, there was no indication of significant bias.
  • The findings were consistent for black tea and green tea, and for Asian and non-Asian populations.

The bottom line?
The similarity in findings between the 2 types of tea might be because both are produced from the same Camelia sinensis plant and have a similar amount of antioxidant catechins (polyphenolic compounds in plants) despite differences in processing, the researchers suggested.

There are few strategies to prevent stroke. However, “The literature is full of this kind of association,” said Dr. Mark Alberts, of Northwestern University in Chicago, who was uninvolved in this study. “We’re not going to be adding tea to the stroke prevention panel anytime soon.”

Others have reported a positive correlation between drinking tea and a lower risk of stroke due to clots, but not stroke due to bleeding.

3/9/09 18:15 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.