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. |
