Dear James,

Both green and black teas come from the tea plant, Camellia sinensis,
a
fragrant evergreen shrub that thrives in China and India. The
differences in
taste and aroma arise from the way the leaves are processed. Leaves
for
black tea are fermented and then fired black in an oven; green-tea
leaves
are simply steamed and dried. That's why green tea tastes lighter and
grassier. Green tea is getting attention these days because many
studies
suggest that drinking a few cups a day may help prevent certain
cancers.

Animal studies have shown that drinking green tea can prevent lung and
digestive system cancers, and there are some hints that the beverage
may
have some of the same effects in humans. When researchers have
compared
groups of people who regularly drink tea to those who don't, the
tea-drinkers show a lower rate of stomach cancer and stroke. And in a
recent
Japanese study, researchers found that breast cancer was about half as
likely to recur or metastasize in women who drank four or more cups a
day.
Researchers say they need to confirm these findings in large clinical
trials
before they can say for sure that the tea was responsible for those
results.
Green tea can also lower cholesterol in rats, but population surveys
have
not been able to show a clear connection between green tea and heart
disease
in people.



How does it work?


Green tea is loaded with powerful antioxidants called polyphenols that
protect cells from the ravages of oxidation, a chemical reaction that
can
lead to cancer and the hardened arteries that cause heart disease. In
fact,
researchers at the University of Kansas say that one antioxidant
called
epigallocatechin gallate, or EGCG, is 25 times more effective in
laboratory
tests than vitamin E at helping cells resist the damage caused by
oxidation
and helping damaged cells repair themselves. Both black and green teas
have
the same total polyphenol content, but green tea has about twice the
EGCG.
All teas also contain a relative of caffeine called theophylline, a
mild
stimulant that helps dilate the bronchial tubes in the lungs.

Researchers conducting a study funded by the Arthritis Foundation
report
that green tea may be useful in treating or preventing rheumatoid
arthritis;
however, it is felt that more research is needed to determine its
exact
role.  In three independent experiments, the mice that researchers
gave
green tea polyphenols (GTP) in water exhibited significantly reduced
incidence of arthritis (ie, 33% to 50% developed arthritis as compared
to
84% to 100% of mice not given GTP in water). According to the release,
mice
given GTP in water were protected significantly from developing
arthritis,
and if they did develop the disease, its severity was mild.

There has been much written lately about the quality of green tea.  In
other
words, all green tea is not created equal.  Quality green tea should
be
clean and taut with the leaf and bud in one peice.  Such leaf sets
also
indicate that the leaves are young and tender, and therefore more
flavorful.
Quality runs in a descending order from bud/one leaf, bud/two leaves,
and so
on.  Teas with incomplete leaves and bits are of inferior quality.
Exceptions are blends, which are composed of more than one tea, broken
black, and of course compressed teas.

There are companies that have been selling organic green tea for many
years.
Consensus is that these companies, whose products are most often found
in
Asian markets, are one's best bet.

Siobhan