"Better to be deprived of food for three days, than tea for
one." (Ancient Chinese Proverb)
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:
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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