April 13 2000. White tea, known mostly to tea connoisseurs,
may have the strongest potential of all teas for fighting cancer, according
to Oregon State University researchers. They presented the first research
ever on white tea March 29th at a national meeting of the American Chemical
Society.
Among the rarest and most expensive varieties of tea, white tea is
produced almost exclusively in China. It belongs to the same species
(Camellia sinensis) as other tea plants, but has a higher proportion
of buds to leaves. The buds are covered by silvery hairs, giving the
plant a whitish appearance.
Some teas are processed more than others. White tea is rapidly steamed
and dried, leaving the leaves Âfresh. Green tea, composed of mainly
leaves, is steamed or fired prior to being rolled. Oolong and black
teas get their dark color and flavor from additional processing.
The researchers think that processing may play a part in teaÂs cancer-fighting
potential. The key is a class of chemicals called polyphenols.
"Many of the more potent tea polyphenols ('catechins') become
oxidized or destroyed as green tea is further processed into oolong
and black teas," says Roderick H. Dashwood, Ph.D., a biochemist
in the universityÂs Linus Pauling Institute and principal investigator
of the study. "Our theory was that white tea might have equivalent
or higher levels of these polyphenols than green tea, and thus be more
beneficial."
Chemical analysis confirmed their theory. White tea contains the same
types of polyphenols as green tea, but in different proportions. Those
present in greater amounts may be responsible for white teaÂs enhanced
cancer-fighting potential, says Dashwood.
Lab tests on four varieties of white tea showed that it may prevent
prevent DNA mutations, the earliest steps leading to cancer. The researchers
say that their latest data indicate that white tea may protect against
colon cancer in particular.
The researchers say more studies are needed to determine whether white
tea actually protects people against cancer. ÂWhite tea, and tea in
general, is a healthy alternative to other popular drinks, such as sodas,Â
says Dashwood. ÂBut to be on the safe side, one should maintain a healthy
lifestyle that includes a diet rich in fruits and vegetables, regular
exercise, and avoidance of smoking.Â
Dr. Dashwood is Associate Professor in the Department
of Environmental and Molecular Toxicology at Oregon State University.
He also is Principal Investigator with the universityÂs Linus Pauling
Institute. Dr. Santana-Rios is a post-doctoral Research Associate with
the Linus Pauling Institute.
Dr. Santana-Rios presented his paper on white tea March 29 at a meeting
of the American Chemical
Society.
