|
Does Green Tea Help the Heart?
By Alice Park
The next time you're offered a
choice between Earl Grey and green tea, you might want to go green.
A new study shows that the
beverage, which is more popular in Eastern cultures, can protect
heart arteries by keeping them flexible and relaxed, and therefore
better able to withstand the ups and downs of constant changes in
blood pressure. Led by Dr. Nikolaos Alexopoulos of Athens Medical
School in Greece, the researchers found that among 14 subjects,
those who drank green tea showed greater dilation of their heart
arteries on ultrasound 30 min. later than those drinking either
diluted caffeine or hot water.
That's because, the scientists
speculate, green tea works on the lining of blood vessels, helping
cells there to secrete the substances needed to relax the vessels
and allow blood to flow more freely. It's the flavonoids in the tea,
which work as antioxidants and help prevent inflammation in body
tissue, that keep the vessels pliable. These substances may also
protect against the formation of clots, which are the primary cause
of heart attacks. "We found very promptly [that] after drinking
green tea, there was a protective effect on the endothelium," says
Dr. Charalambos Vlachopoulos, a cardiologist and one of the authors
of the study.
All it took, says Vlachopoulos, was
6 g of green tea, which amounts to 3 to 4 cups. To make sure the
dilation effect was not due to the small amounts of caffeine found
in green tea, the group compared the arterial sizes in the green-tea
drinkers with those consuming a diluted caffeine beverage and found
no change in arterial size in the caffeine drinkers. Even more
intriguing, the beneficial effect seems to be long-lasting and
cumulative.
When the doctors measured the
green-tea drinkers' arteries two weeks after daily consumption of
the beverage, they found that their vessels were more dilated than
they had been at the beginning of the study. "It's something that
needs to be investigated, but we think that if someone takes green
tea for one or two months, the beneficial effect will be even
greater," says Vlachopoulos.
But experts caution that one study
isn't enough to catapult green tea to wonder-drink status. Dr.
Robert Eckel, a professor at the University of Colorado, Denver, and
past president of the American Heart Association, notes that
endothelial function is affected by a number of factors, including
large doses of vitamins E and C.
"Green-tea consumption may have
beneficial effects on the arteries, but we should stop short of
translating that into a recommendation that everybody should be
drinking green tea because it's been proven to reduce heart attacks
and strokes," he says. He acknowledges, however, that early studies
hint that green tea may be a good addition to a heart-healthy diet.
The American Heart Association does not yet include the beverage in
its dietary recommendations, but more studies like this one may
change that. In the meantime, if you're drinking tea, it might not
be such a bad idea to go green. --
Time.com
Click
Here To Have Your Say On This Story
Brudirect.com News
|