Cancer-preventive potential of white tea

March 20, 2000

Study finds rare tea may be healthiest of all

SAN FRANCISCO, March 29 - Known mostly to tea connoisseurs, white tea may have the strongest potential of all teas for fighting cancer, according to Oregon State University researchers. They will present their research today - the first on white tea - at the 219th national meeting of the American Chemical Society, the world's largest scientific 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 virtually "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 theorize 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.

Encouraged by reports of cancer-fighting chemicals in green tea, the researchers decided to test white tea to determine whether it has similar qualities. They brewed four varieties of white tea and subjected each to a laboratory test using bacteria. The test, called the Salmonella assay, determines whether a chemical can cause or prevent DNA mutations, the earliest steps leading to cancer.

White tea inhibited mutations more efficiently than green tea. This means it may have more potential to prevent cancer than green tea, says Gilberto Santana-Rios, Ph.D., a post-doctoral research associate with the institute, located in Corvallis, Ore.

The researchers, now performing experiments in rats, report that their latest data indicate that white tea may protect against colon cancer in particular. They attribute this to elevated levels of particular liver enzymes.

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 will present his paper, TOXI 85, on Wednesday, March 29, at 7:00 p.m. in the Sheraton Palace Concert Ballroom, Lobby Level.
-end-


American Chemical Society

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.