A study by an American research team has demonstrated that tai chi exercise (TC) and supplementation with green tea polyphenols (GTP) can benefit bone remodeling and muscle strength in postmenopausal women by reducing oxidative stress damage. One hundred and seventy-one postmenopausal women with osteopaenia (low bone mineral density) were divided into four groups: placebo – placebo pill without TC; GTP (500 mg / day) without TC; placebo pill plus TC (three times per week); or GTP plus TC. The treatment phase of the study lasted for six months. The results showed that consumption of GTP (at a level equivalent to about four to six cups of steeped green tea daily) and TC independently enhanced markers of bone health. Both GTP and TC were also found to reduce levels of biological markers of oxidative stress, suggesting that they have anti-inflammatory activity. TC participants also reported significant beneficial effects in quality of life in terms of improved emotional and mental health. (Effect of green tea polyphenols and Tai Chi exercise on bone health in postmenopausal women with low bone mass: a 24-week placebo-controlled randomized trial. FASEB Journal. 2011;25:594.3).

Beneficial antioxidant substances found in green tea are absorbed by eye tissues, suggesting that green tea consumption could protect the eye against oxidative stress that can contribute to the development of glaucoma, cataract and eye diseases. A new Hong Kong study is the first to show that green tea catechins are actually passed from thegastrointestinal tract into the tissues of the eye. Analysis of eye tissues from rats that were fed green tea extract showed that eye structures absorbed significant amounts of individual catechins. The retina absorbed the highest levels of gallocatechin, while the aqueous humor tended to absorb epigallocatechin. The effects of green tea catechins in reducing harmful oxidative stress in the eye lasted for up to 20 hours. (Green tea catechins and their oxidative protection in the rat eye. J Agric Food Chem. 2010 Feb 10;58(3):1523-34).

Green tea has been shown to inhibit growth of Helicobacter pylori, which is a carcinogen and the most important risk factor for gastric cancer. Researchers also evaluated the effects of green tea on the development of Helicobacter-induced gastritis in an animal model and demonstrated that chi benefits arthritis. Green tea consumption can prevent gastric mucosal inflammation if ingested prior to exposure to Helicobacter infection. (Green tea inhibits Helicobacter growth in vivo and in vitro. Int J Antimicrob Agents. 2009 May;33(5):473-8).

A meta-analysis of data from nine studies involving 194,965 individuals suggests that daily consumption of three cups per day of either green or black tea could prevent the onset of ischaemic stroke. (Green and black tea consumption and risk of stroke: a meta-analysis. Stroke. 2009 May;40(5):1786-92).

However, authors of a Cochrane Database systematic review of fifty-one studies involving more than 1.6 million participants have concluded that there was insufficient evidence to give any firm recommendations regarding green tea consumption for cancer prevention. (Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev. 2009 Jul 8;(3):CD005004).

Evidence for the manifold benefits of green tea continues to mount. Recent studies have shown a significant preventive effect against colorectal and oral cancer in women who drank green tea regularly, and a 48% reduction in risk of developing advanced prostate cancer in men who drank five or more cups a day (over 14 years). Green tea extract may also be a promising treatment for skin disorders such as psoriasis and for preventing lethal bacterial sepsis. Meanwhile black tea appears to decrease bone loss in elderly women, reduce plasma glucose concentrations and stimulate insulin production, and have favourable effects on markers of coronary heart disease.