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.