Eating Well

White Tea, Rarer, May be Even Healthier Than Green

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 “fresh.” 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 tea’s 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 university’s 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 tea’s 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. “White tea, and tea in general, is a healthy alternative to other popular drinks, such as sodas,” says Dashwood. “But 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.”

Dr. Dashwood is Associate Professor in the Department of Environmental and Molecular Toxicology at Oregon State University. He also is Principal Investigator with the university’s 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.

For this work Palermo received the award for best poster in the chemical carcinogenesis specialty section at the meeting of the Society of Toxicology in March. Now she is studying exactly how green tea inhibits the AH receptor. After she graduates Palermo plans to study links between environmental agents and childhood leukemia.

In addition to Palermo and Gasiewicz, other authors are former post-doctoral associate Jose Martin Hernando and chemist Andrew Kende, who teased apart the components of green tea extract; and Stephen Dertinger, a former student who first had the idea to test green tea’s effects on the AH receptor. The work was funded by the National Institute of Environmental Health Sciences and the American Institute for Cancer Research.