W A S H I N G T O N, May 22, 2001 -- You won't find it served atyour dentist's office just yet, but drinking black tea betweenmeals may help reduce cavities and plaque, researchers said onTuesday.
New studies, funded by the Tea Trade Health ResearchAssociation, found several doses of black tea every day notonly reduced plaque build-up but also helped control bacteria.
"We found that the black tea infusion can inhibit orsuppress the growth of bacteria that promotes cavities andaffect their ability to attach to tooth surfaces," ChristineWu, professor of periodontics at the University of Illinois andlead researcher on one part of the study.
Wu said that while earlier studies in Japan have shown thecavity-fighting benefits of green tea, known for its richantioxidants, her team chose to focus on black tea, which ismore popular in western culture.
The research is part of a collaborative study done inconjunction with the College of Dentistry at the University ofIowa and the Institute of Odontology at Goeteborg University inSweden. The findings were presented at a meeting of theAmerican Society for Microbiology in Orlando, Florida.
300 Species of Bacteria
Dental plaque contains more than 300 species of bacteriathat adhere to tooth surfaces and produce cavity-causing acid.Plaque is also a leading cause of gum disease.
A specific element of black tea, called polyphenols, killedor suppressed cavity-causing bacteria from either growing orproducing acid, according to Wu's study. The tea also affectedthe bacterial enzymes and prevented the formation of thesticky-like material that binds plaque to teeth.
Participants in the study rinsed with tea for 30 seconds,five times, waiting three minutes between each rinse.
"We were trying to simulate what people did while sippingtea," Wu said.
A similar study by Goeteborg University, where participantsrinsed with tea for one minute 10 times per day, showedcomparable results. Both studies showed that the more peoplerinsed, the more their plaque and bacteria levels fell.
In the University of Iowa study, researchers looked at theimpact of black tea's fluoride content on preventing cavitiesbut found the benefits less clear. They exposed pre-cavitylesions to black tea but saw little change, suggesting thattea's cavity-fighting ability stems from a complicated reactionbetween it and bacteria.
Fluoride Not A Factor?
"We had very little results, which implies that if tea ishaving a result in normal use it's not from fluoride," saidJames Wefel, professor and director of the Dows Institute ofDental Research at the University of Iowa.
Of course, to help prevent cavities the tea must truly be"black," without sugar, milk, honey or other additives.Researchers also stressed drinking black tea should not replacetraditional oral hygiene.
"Tea will affect the plaque formation but one has to brushtheir teeth to remove the plaque," Wu said. "It's a must." And while black tea may fight cavities, it does not combattooth stains.
"It is going to stain (people's) teeth, but at least weknow it's good for oral health," Wu said.