THE
POWER OF TEA
After
water, tea is the most commonly consumed beverage
in the world, and drinking it has been linked to slew
of health benefits. Now recent research shows that
the billions of people who drink it may be on to something.
Tea
and Heart
One
area in which tea is supposed to be beneficial is
in fighting cardiovascular disease. A recent study
published in circulation, the journal of the American
Hear Association, found that heart patients who drank
copious cups of tea were less likely to die 3 or 4
years after a heart attack.
Researchers
at Beth Israel Deaconess Medical Center and the Harvard
Medical School interviewed 1900 patients who had been
hospitalized following a heart attack. The subjects
were asked about their tea consumption over the last
year and divided into three groups : Non-drinkers,
moderate drinkers (fewer than 14 cups per week), and
heavy drinkers (14 or more cups per week). After a
follow-up period of almost 14 years, the moderate
group was 28% less likely to die, while the heavy
use group had a 44% lower death rate, after taking
into account differences in lifestyle (such as smoking
and exercise) and medical conditions.
"If
the true effect of tea in clinical trials is anywhere
near what we saw, this will be of great public health
importance," says Kenneth Mukamal, MD, assistant
professor of medicine at Harvard Medical School and
an associate in medicine at Beth Israel Deaconess
Medical Center. Additional research needs to be done,
but he hopes that this work will spur controlled studies
in the future.
What's
in those tea leaves?
The
curative power of tea may be due to the antioxidants
it contains known as flavonoids, which are thought
to prevent cardiovascular disease. Flavonoids may
help lower LDL ("bad") cholesterol, and
studies have shown that they may have an anti-clotting
effect as well. They are found naturally in green
and black tea, as well other foods such as apples,
anions, and broccli.
A
recent study appearing in current opinion in Lipidology
analyzed previously published research on the health
benefits of tea and found that 150 milligrams of flavonoids
- the amount found in a cup of brewed tea - was enough
to have an immediate antioxidant effect. Consuming
higher doses of flavonoids, or additional cups or
tea, increased the effect.
Drinking
tea may fight cancer
Tea's
benefits may derive from more than just flavonoids,
however. It also contains catechins, another powerful
antioxidant belonging to a group of chemicals known
as polyphenols. Green tea, which is the least fermented
type of tea, contains the most catechins, followed
by oolong and black teas. Research has shown that
catechins may halt tumor cell growth and protect healthy
cells from damage.
At
a recent meeting of the American Association for Cancer
Research, researchers at the Keck School of Medicine
at the University of Southern California presented
a study conducted with colleagues at the Shanghai
Cancer Institute in China that showed tea drinkers
were about half as likely to develop stomach or esophageal
cancer as nontea drinkers.
Over
18,000 men in Shanghai, China were followed and the
232 subjects who developed one of these types of cancers
were compared to 772 similar subjects without cancer.
Researchers measured epigallocatechin (EGC), a substance
that's produced when catechins break down, and found
that subjects who had more EGC in their urine had
a lower cancer risk.
This
was the first study that used a biomarker to measure
substances found form drinking tea, as "I'm not
sure our study means people should fill up their cupboards
with tea," Says Mukamal, "but it points
to the possible health benefits." Considering
there are no risks to drinking tea - if you don't
load it up with sugar and high fat milk - he says
it may make sense to discuss it with your doctor and
add it to whatever you're already doing.
Sources
:
- Beth
Israel Deaconess Medical Center/Harvard
- Medical
School
- USC
Keck School of Medicine
- Beltsville
Human Nutrition Research Center
- Current
Opinion in Lipidology
- General
Dentistry
- University
of Chicago, Tang Center for Herbal
- Medicine
Research
.
