May 17, 2001

Contact: Sharon Butler(312) 355-2522[email protected]

Embargoed for release until Tuesday, May 22, 11:45 a.m. ET


A cup a day may keep the dentist away

Black tea can help fight cavities and prevent gum disease, according to research presented at the annual American Society for Microbiology meeting.

The beverage interferes with harmful bacteria in the mouth that form dental plaque, said Christine Wu, professor of periodontics at the UIC College of Dentistry, who led the study.

Wu and her colleagues found that chemical components in black tea, called polyphenols, suppressed the growth of cavity-causing bacteria in plaque and reduced acid production levels.

The polyphenols also inhibited an enzyme produced by the bacteria, called glucosyltansferase, thus preventing the formation of the matrix material by which dental plaque adheres to tooth surfaces.

In addition, the size and stickiness of dental plaque were reduced because certain bacteria, when exposed to black tea, lost their ability to form aggregates with other bacteria.

Dental plaque consists of more than 300 species of bacteria embedded in a chemical and biological matrix that adheres to the tooth surface. The bacteria in plaque ferment dietary sugars to produce acid, which leads to the formation of cavities on tooth surfaces. Dental plaque also causes gum disease, a leading cause of tooth loss in adults.

The study included several trials in which volunteers rinsed their mouths with black tea at different intervals. In one trial, those who rinsed with black tea for one minute 10 times a day had less plaque accumulation. In another, a single 30-second rinse had no effect, but multiple rinsings prevented bacteria from further growth and lowered acid production.

"If sequenced properly between meals and normal oral hygiene, drinking black tea could reduce the number of cavities and prevent periodontal disease," Wu said.

Black tea, an aqueous infusion of dried leaves of the Camellia sinensis plant, is the most popular beverage worldwide, second only to water. Per capita consumption averages four fluid ounces per day.

Other researchers involved in the study were James Wefel, director of the Dows Institute of Dental Research at the University of Iowa, and Peter Lingstrom, associate professor of cariology at the Institute of Odontology, Goteborg University, Sweden.

The Tea Trade Health Research Association in London supported this work.


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