May 27, 2009

TEA TIME

Meta-analysis finds lower risk of stroke among tea drinkers:

The results of a meta-analysis published in the May 1, 2009 issue of the American Heart Association journal Stroke revealed that men and women who consumed at least three cups of green or black tea per day had a lower risk of stroke than those who consumed less than one cup.
For their review, Lenore Arab, PhD and her colleagues at UCLA's David Geffen School of Medicine selected 9 epidemiological studies that included data on tea intake and fatal or nonfatal stroke outcomes. The studies included a total of 194,965 participants in 6 different countries, among whom 4,378 strokes occurred.
The pooled analysis uncovered a 21 percent lower risk of fatal or nonfatal stroke among those who consumed three or more cups of tea per day compared to those whose intake was reported at less than one cup per day. The findings involved participants from diverse geographical areas and were consistent whether green or black tea was consumed.
Although the analysis did not break down stroke according to type, the authors believe that the association observed is likely to be due primarily to tea's effect on ischemic stroke. In their discussion of possible mechanisms for tea against stroke, they note that although tea's antioxidant and anti-inflammatory actions are frequently cited, green and black tea have also been demonstrated to reduce blood pressure in an experimental model of hypertension, a condition that is a strong risk factor for stroke. Additionally, tea has been shown to enhance endothelial function, which, when reduced, impairs cerebral blood flow. Furthermore, a compound found in tea known as theanine readily crosses into the brain, where it may provide a neuroprotective effect.
"The observational, epidemiological research in humans is strongly supportive of the hypothesis that tea consumption, at the level of greater than or equal to 3 cups per day, either as green or black tea, reduces the risk of occurrence of stroke, stroke volume, and mortality from stroke," the authors conclude.

No comments:

Post a Comment