Thee tegen een beroerte*
Uit een analyse van negen studies onder 195.000 mensen waarvan 4.378 mensen een beroerte gehad hadden blijkt dat het drinken van
thee zowel groene als de gewone zwarte de kans op een beroerte duidelijk doen afnemen. 3 koppen per dag geven 21% minder kans op een beroerte. Nog eens 3 koppen extra per dag doen de kans wederom met 21% afnemen. Totaal geven 6 koppen per dag al 42% minder kans op een beroerte.
De resultaten zullen nog wel in een echte trial moet worden bevestigd temeer
omdat Lipton (Unilever) de sponsor voor deze studie was.
Stroke Risk Reduced By Green, Black Tea
Drinking at least three cups of green or black tea a day can significantly reduce the risk of stroke, a new UCLA study has found. And the more you drink, the better your odds of staving off a
stroke.
The study results, published in the online edition of Stroke: Journal of the American Heart Association, were presented at the American Heart Association's annual International Stroke Conference in San
Diego, Calif.
The UCLA researchers conducted an evidence-based review of all human observational studies on stroke and tea consumption found in the PubMed and Web of Science archives. They found nine studies describing 4,378 strokes among nearly 195,000 individuals, according to lead author Lenore Arab, a professor of medicine in the division of general internal medicine and health services research at the David Geffen School of Medicine at UCLA.
"What we saw was that there was a consistency of effect of appreciable magnitude," said Arab, who is also a professor of biological chemistry. "By drinking three cups of tea a day, the risk of a stroke was reduced by 21 percent. It didn't matter if it was green or black
tea."
And extrapolating from the data, the effect appears to be linear, Arab said. For instance, if one drinks three cups a day, the risk falls by 21 percent; follow that with another three cups and the risk drops another 21 percent.
This effect was found in tea made from the plant Camellia sinensis, not from herbal teas.
There are very few known ways to reduce the risk of stroke, Arab said. And developing medications for stroke victims is particularly challenging, given that the drug has to get to the stroke-damaged site quickly because damage occurs so fast. Arab said that by the time a stroke victim gets medical care, it's nearly too late to impede the damage.
"That's why these findings are so exciting," she said. "If we can find a way to prevent the stroke, or prevent the damage, that is simple and not toxic, that would be a great advance."
Though no one is certain which compounds in tea are responsible for this effect, researchers have speculated that the antioxidant epigallocatechin gallate (EGCG) or the amino acid theanine may be what helps. Antioxidants are believed to help prevent coronary artery
disease.
"And we do know that theanine is nearly 100-percent absorbed," Arab said. "It gets across the blood-brain barrier and it looks a lot like a molecule that's very similar to glutamate, and glutamate release is associated with stroke.
"It could be that theanine and glutamate compete for the glutamate receptor in the brain," she added.
Although a randomized clinical trial is needed to confirm this effect, the findings suggest that drinking three cups of green or black tea a day could help prevent an ischemic stroke.
Study co-authors with Arab are Weiqing Liu, a senior statistician in the UCLA Department of Biomathematics, and David Elashoff, associate professor of medicine in the division of general internal medicine and health services search at the David Geffen School of Medicine at
UCLA.
The Unilever Lipton Institute of Tea funded this study.
The General Internal Medicine and Health Services Research Divison in the department of medicine at the David Geffen School of Medicine at UCLA provides a unique interactive environment for collaborative efforts between health services researchers and clinical experts with experience in evidence-based work. The division's 100-plus clinicians and researchers are engaged in a wide variety of projects that examine issues related to access to care, quality of care, health measurement, physician education, clinical ethics and doctor-patient communication. Researchers in the division have close working relationships with economists, statisticians, social scientists and other specialists throughout UCLA and frequently collaborate with their counterparts at the RAND Corp. and the Charles Drew University of Medicine and
Science.
Contact: Enrique Rivero
University of California - Los Angeles (April
2009)
