For those of you already downing bucket-loads of green tea because of its ability to ward off all manner of ailments, here are just a few more reasons to feel pleased with your choice of beverage...

Green tea has beneficial properties for teeth and gums and can help prevent periodontal disease. A Japanese team following the diet of 940 elderly men (aged 49-59) who drank green tea on a regular basis found that periodontal disease occurred at a lower rate in those who drank more green tea (at least one cup a day) than men who did not. (Relationship between intake of green tea and periodontal disease. J Periodontol. 2009 Mar;80(3):372-7).

Another Japanese group has shown that green tea catechin (GTC) extract can inhibit bone resorption induced by inflammation due to bacterial infection of the gums (the cause of periodontal disease). It achieves this in two ways: by inhibiting the production of pro-inflammatory cytokines by cells in gum tissue and also by directly inhibiting the formation of osteoclasts (cells which break down bone). (Green tea catechin inhibits lipopolysaccharide-induced bone resorption in vivo. J Periodontal Res. 2009 Jul 8. [Epub ahead of print]).

Hong Kong researchers have found three GTCs to have positive effects on bone metabolism through a dual process of promoting osteoblast (bone building cell) activity and inhibiting osteoclast (bone absorbing cell) activity. The authors conclude that the health benefits of green tea may thus extend to preventing osteoporosis. (Effects of Tea Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate, on Bone Metabolism. J Agric Food Chem. 2009 Aug 4. [Epub ahead of print]).

Green tea extract (GTE) has also shown promise in preventing oral cancer. A randomised, placebo-controlled phase II trial was carried out in America in 41 patients with oral leukoplakia (a pre-cancerous condition) to establish correct dosing and look for toxicity. Of those taking green tea at the two highest doses, 58.8% had a clinical response, compared with 36.4% in the lowest extract dose and 18.2% in the placebo arm. Biopsies of oral tissue collected at baseline and 12 weeks suggested anti-angiogenic effects as a potential mechanism of action for GTE.

Negative side effects, including insomnia and nervousness, were mostly seen in the high-dose group, but the compound produced no significant toxicity. (Phase II randomized, placebo-controlled trial of green tea extract in patients with high-risk oral premalignant lesions. Cancer Prev Res (Phila Pa). 2009 Nov;2(11):931-41).

And just in case you still need a reason to convince you to get the kettle on...