The beverage Green tea too, as Black tea & Oolong tea, is manufactured from evergreen tea plant Camellia sinensis by a process of oxidation: drying & steaming. Mildly oxidized Green tea contains higher levels of antioxidants (molecules capable of slowing or preventing the oxidation of other molecules) than fully oxidized Black tea.
The human body constantly produces unstable molecules called oxidants, also known as free radicals. These oxidants, as everything else in the universe, are in search of stability. The fast track to stability, i.e. getting rich being stealing, those free radicals make haste to steel electrons from other molecules at their own sweet free will. Bitter is the result to the victim: the process result in damage to cell proteins leaving those vulnerable to cancer.
Green tea is rich in polyphenols, which include the powerful antioxidants called catechins. Though these polyphenols are found in Black tea as well as in Oolong tea, some claim the polyphenols in green tea have superior cancer-preventing abilities. Polyphenol antioxidant found in Green tea, Black tea & Oolong tea, as all other antioxidant do, scavenge & seize free radicals (unstable molecules called oxidants) to inhibit specific enzyme activities that result in cancer. All varieties of tea from Camellia sinensis contain polyphenols. The polyphenol most widely recognized with prevention of cancer is EGCG (epigallocatechin-3-gallate). Beverages Green tea as well as Black tea prepared with boiling water result in release of over 80 percent of its catechins.
Green tea: general perception against cancer
Numerous clinical studies based on segments of world populations have brought about the perception that Green tea helps protect humans against the onslaught of cancer. On worldwide level, it is observed higher intake of Green tea relates to lower percentage of cancer patients, the finest example being Japan. Then again, further studies on this general perception alone do not determine therapeutic & preventive qualities of Green tea against cancer. However emerging clinical studies still continue to suggest that the polyphenols in green tea may play an important role in the prevention of cancer.
Therapeutic & preventive qualities of Green tea: the Laboratory tests Vs Human studies
The laboratory studies on the medical properties of Green tea making use of animals provide proof to the effect that catechins reduce the number and size of tumors thereby inhibiting the growth of cancer cells. However, the human studies haven’t yet been conclusive most possibly owing to vital factors such as food habits, cultural habits, life styles, & living environment being at variance with different segments of populations around the world. Research is being continued on therapeutic & preventive qualities of Green tea on all types of cancer.
“Despite the large number of included studies, the jury still seems to be out on the question of whether green tea can in fact prevent the development of various cancer types,” Katja Boehm, a member of the Unconventional and Complementary Methods in Oncology Study Group in Nuremburg, Germany, said in the news release dated July 14, 2009 issued by The Cochrane Collaboration.
Green tea Vs. Skin cancer: Laboratory tests on mice
In the year 2000, based on mice model laboratory studies funded by National Institute of Environmental health Sciences (NIEHS) and the National Cancer Institute led by Santosh K. Katiyar, Ph.D.University of Alabama reported that drinking Green tea may be useful in preventing and treating a variety of human skin disorders.
Antioxidant, epigallocatechin-3-gallae (EGGCG) contained in polyphenols protect the skin from ultraviolet radiation and prevent formation of skin tumor. “Green tea prevents UV radiation induced suppression of the immune system, which has been considered a risk factor for the development of skin cancer,” Says Dr. Katiyar.
“The next area of research will be to study whether the data we obtained in animal models is equally useful for human beings,” Dr. Katiyar says.
Green tea Vs. Breast cancer: Laboratory tests on mice
In April 2008, Jian-Wei Gu of the University of Mississippi Medical Center in Jackson presented a study with indications that Green tea antioxidant EGCG (epigallocatechin-3-gallate) significantly slowed breast cancer growth in female mice.
Two groups of female mice selected for the study were injected breast cancer cells. While the control group of female mice was fed with drinking water, the test group was fed with a solution of the Green tea antioxidant in water for five weeks. The results showed that treatment with the Green tea antioxidant EGCG (epigallocatechin-3-gallate) decreased tumor size by 66% and weight by 68% in comparison with the control group.
The results of the study suggested anticancer effects of high content of EGCG.
Green tea Vs prostate cancer: human studies
In a human study, Philadelphia-based researchers at Feist-Weiller Cancer Center tested 26 patients of prostate cancer, who were scheduled for radical prostate surgery with compound called Polyphenon E for an average of 34 days equivalent of 12 cups of Green tea. The study found a significant reduction, in some patients as high as 30%, in levels of biomarkers – molecules HGF (hepatocyte growth factor), VEGF (vascular endothelial growth factor), which are indicators of developing cancer. The team leader of the study Dr James Cardelli stated said the compound Polyphenon E, “may have the potential to lower the incidence and slow the progression of prostate cancer.”
Green tea Vs. esophageal cancer: human studies
During October 1, 1990, through January 31, 1993, Shanghai Cancer Institute Shanghai, People’s Republic of China carried out a study of Therapeutic qualities on 1016 patients diagnosed with esophageal (gullet) cancer. The findings in this test on protective effects of green tea consumption were consistent with studies in laboratory animals: Green tea can inhibit esophageal carcinogenesis. Further studies have been carried out since then.
