Those who drink more than three cups a day had a 21 percent lower risk of stroke than those who sipped less than a cup daily, said study author Dr. Lenore Arab, a professor of medicine and biological chemistry at the University of California, Los Angeles.
She conducted a meta-analysis, pooling the results of nine published studies involving 4,378 strokes among more than 194,000 people, many from Asia. Black tea and green tea were studied, and it was typically caffeinated.
The result was that increased tea consumption decreased the risk. "We see it consistently in every study," Arab said. The research was funded by the Unilever Lipton Institute of Tea, a research and development arm of Lipton Tea.
Exactly how tea reduces stroke risk isn't clear, she said. Among the suggested ways it might work is by anti-inflammatory action. An amino acid found in black and green tea, theanine, may protect the brain.
The tea study is stronger than the coffee study, said Dr. Ralph Sacco, chairman of the department of neurology at the University of Miami Miller School of Medicine.
The coffee study, though interesting, "still needs confirmation," he said. The research was like a snapshot in time, asking people about coffee habits at a given point.
Better, he said, is to do a study in which participants are followed over time to determine if there is a link between coffee drinking and stroke.
He also wondered if coffee drinking might have decreased among those who were diagnosed with heart or other problems and were advised to reduce their coffee intake. "I don't feel this study is strong enough to recommend people drink coffee to reduce the risk of stroke," he said.
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