Green tea may boost oral health and reduce tooth loss

March 25, 2010

     Drinking one cup of green tea daily may improve dental health and reduce the risk of loosing teeth by about 20 % according to a new study from Japan and drinking more cups appears to confer additional risk reductions, with five or more cups a day associated with a 23 % reduction in risk, according to findings from the Ohsaki Cohort 2006 Study. The link does appear to be biologically plausible, state the authors, led by Yasushi Koyama from Tohoku University Graduate School of Medicine. Previous studies have reported that green tea catechins may inhibit the action of oral bacteria linked to the development of periodontal disease, they said.
     “A number of experimental studies have shown that green tea catechins inhibit oral bacteria, while some experiments have indicated that the concentration of tea catechin conferring the above effect should be more than 100 mg/100 ml,” wrote the authors. “A typical preparation of green tea contains a catechin concentration of 50–150 mg/100 ml.
“Therefore, this amount of catechin contained in one cup of green tea might be sufficient to aid tooth retention,” they added. 
     The majority of science on tea has looked at green tea, with benefits reported for reducing the risk of Alzheimer's and certain cancers, improving cardiovascular and oral health, as well as aiding in weight management. Green tea contains between 30 to 40 % of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 to 10 %. Oolong tea is semi-fermented tea and is somewhere between green and black tea.
     Dr. Koyama and co-workers analysed data from 25,078 people aged between 40 to 64 years. By measuring tooth loss in people with up to 20 teeth still remaining, the researchers calculated that one to two cups of green tea per day was associated with an 18 % reduction in tooth loss risk. The same reduction was calculated for three to four cups per day, while five or more cups were associated with a 23 % reduction in risk. If the researchers limited or extended the data for people with less than ten, or up to 25 teeth, the same protective levels of green tea consumption were observed. The study is p Published online ahead of print in the journal Preventive Medicine.