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Is any other food or drink reported to have as many health
benefits as green tea? The Chinese have known about the medicinal
benefits of green tea since ancient times, using it to treat
everything from headaches to depression. In her book Green Tea:
The Natural Secret for a Healthier Life, Nadine Taylor states
that green tea has been used as a medicine in China for at least
4,000 years.
Today, scientific research in both Asia and the west is
providing hard evidence for the health benefits long associated
with drinking green tea. For example, in 1994 the Journal of the
National Cancer Institute published the results of an
epidemiological study indicating that drinking green tea reduced
the risk of esophageal cancer in Chinese men and women by nearly
sixty percent. University of Purdue researchers recently concluded
that a compound in green tea inhibits the growth of cancer cells.
There is also research indicating that drinking green tea lowers
total cholesterol levels, as well as improving the ratio of good
(HDL) cholesterol to bad (LDL) cholesterol.
To sum up, here are just a few medical conditions in which
drinking green tea is reputed to be helpful:
- cancer
- rheumatoid arthritis
- high cholesterol levels
- cariovascular disease
- infection
-
impaired immune function
What makes green tea so special?
The secret of green tea lies in the fact it is rich in catechin
polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is
a powerful anti-oxidant: besides inhibiting the growth of cancer
cells, it kills cancer cells without harming healthy tissue. It has
also been effective in lowering LDL cholesterol levels, and
inhibiting the abnormal formation of blood clots. The latter takes
on added importance when you consider that thrombosis (the
formation of abnormal blood clots) is the leading cause of heart
attacks and stroke.
Links are being made between the effects of drinking green tea
and the "French Paradox." For years, researchers were puzzled by
the fact that, despite consuming a diet rich in fat, the French
have a lower incidence of heart disease than Americans. The answer
was found to lie in red wine, which contains resveratrol, a
polyphenol that limits the negative effects of smoking and a fatty
diet. In a 1997 study, researchers from the University of Kansas
determined that EGCG is twice as powerful as resveratrol, which may
explain why the rate of heart disease among Japanese men is quite
low, even though approximately seventy-five percent are
smokers.
Why don't other Chinese teas have similar health-giving
properties? Green, oolong, and black teas all come from the leaves
of the Camellia sinensis plant. What sets green tea apart is the
way it is processed. Green tea leaves are steamed, which prevents
the EGCG compound from being oxidized. By contrast, black and
oolong tea leaves are made from fermented leaves, which results in
the EGCG being converted into other compounds that are not nearly
as effective in preventing and fighting various diseases.
Other Benefits
New evidence is emerging that green tea can even help dieters.
In November, 1999, the American Journal of Clinical
Nutrition published the results of a study at the University
of Geneva in Switzerland. Researchers found that men who were given
a combination of caffeine and green tea extract burned more
calories than those given only caffeine or a placebo.
Green tea can even help prevent tooth decay! Just as its
bacteria-destroying abilities can help prevent food poisoning, it
can also kill the bacteria that causes dental plaque. Meanwhile,
skin preparations containing green tea - from deodorants to creams
- are starting to appear on the market.
Harmful Effects?
To date, the only negative side effect reported from drinking
green tea is insomnia due to the fact that it contains caffeine.
However, green tea contains less caffeine than coffee: there are
approximately thirty to sixty mg. of caffeine in six - eight ounces
of tea, compared to over one-hundred mg. in eight ounces of
coffee.
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