Among their many biological activities, the predominant polyphenols in green tea―EGCG, EGC, ECG, and EC―and the theaflavins and thearubigins in black teas have antioxidant activity. These chemicals, especially EGCG and ECG, have substantial free radical scavenging activity and may protect cells from DNA damage caused by reactive oxygen species. Tea polyphenols have also been shown to inhibit tumor cell proliferation and induce apoptosis in laboratory and animal studies. In other laboratory and animal studies, tea catechins have been shown to inhibit angiogenesis and tumor cell invasiveness. In addition, tea polyphenols may protect against damage caused by ultraviolet (UV) B radiation, and they may modulate immune system function. Furthermore, green teas have been shown to activate detoxification enzymes, such as glutathione S-transferase and quinone reductase, that may help protect against tumor development. Although many of the potential beneficial effects of tea have been attributed to the strong antioxidant activity of tea polyphenols, the precise mechanism by which tea might help prevent cancer has not been established.
Cancer Prevention Benefits of Tea In The News:
Long Term tea consumption may reduce risk of ovarian cancer
Women who start drinking tea at a younger age have been found to benefit from a lower risk of ovarian cancer later on in life. A study surveyed tea-drinking habits of 1000 women with an average age of 59 over a period of two years. Data included daily consumption, tea type and when they first started. Results showed that women without cancer were more likely to be tea drinkers from an earlier age and, on average, consumed more cups a day than those diagnosed with the illness. Authors of the study suspect that flavonoids may be responsible for these effects and encourage the consumption of tea because of the potential benefit in preventing this common and deadly disease.
The Telegraph, Nov 2012
Green tea related to lower risk of cancer of the digestive system
A large-scale study suggests that green tea may play a role in lowering risks of colon, stomach and throat cancers for older women. Scientists from Vanderbilt University School of Medicine in Nashville followed 69,000 women for a period of ten years and found that those who drank green tea at least three times a week were 14 percent less likely to develop a cancer of the digestive system. Furthermore, the study found that women who drank green tea for at least 20 years were 27% less likely than non-drinkers to develop any digestive system cancer. Although researchers admit only clinical studies can establish a direct link, they did account for other factors like diet, income, exercise habits and medical history in their study and still found a benefit of drinking green tea.
Reuters, Oct 2012
Green tea may slow prostate cancer
A study that was presented at the conference of American Association for Cancer Research suggests that green tea may slow the progression of prostate cancer. Drinking six cups of brewed green tea was shown to lower the levels of some disease-associated inflammation. The study focused on 67 prostate patients scheduled for a type of surgery known as a prostatectomy, where the prostate is removed, and found that drinking tea in preceding weeks produced a noticeable drop in both serum prostate-specific antigen (PSA) concentrations and PSA protein expression. Researchers explain that reduction in inflammation may be an indication that green tea may also inhibit tumor growth. The study builds on previous research that suggests that flavonoids may be associated with a lower risk of developing prostate cancer.
US News, Oct 2012
Laboratory research finds green tea extract may eliminate skin cancer
A new lab study has found that green tea extracts may be able to destroy skin cancer cells. The University of Strathclyde team discovered that a compound found in green tea called epigallocatechin gallate, or EGCG, is able to either prevent skin tumors from growing, shrink them or even make them disappear. After one month of treatment, 40% of tumors of one type of human skin cancer were entirely removed, whereas a further 30% shrank during the same period. One reason for these successful results may be the fact that, for the first time, EGCG compounds were delivered directly to the tumors using specific proteins that target tumors’ receptors for different biological substances.
The Telegraph, Aug 2012
Study says green tea extract ‘is cancer aid’
A green tea extract may help patients with a form of leukaemia, a study says. The tea, discovered in China nearly 5,000 years ago, has long been thought to have health benefits. But the team from the Mayo Clinic in the US found it appeared to improve the condition of four patients with chronic lymphocytic leukaemia (CLL).
BBC News Dec 22, 2005
Catechins found in Green Tea related to Cancer Therapy
DNA and RNA are binding targets of green tea catechins, revealing their potential use in cancer therapy. “The significance of catechins, the main constituent of green tea, is being increasingly recognized with regard to cancer prevention. Catechins have been studied for interactions with various proteins, but the mechanisms of the various catechins are not yet elucidated,” investigators in Japan reported.
Drug Week, 8/18/06
Components found in tea affect neoplastic cell transformation and carcinogenesis
Accumulating research evidence suggests that many of dietary factors, including tea compounds, may be used alone or in combination with traditional chemotherapeutic agents to prevent or treat cancer. The potential advantage of many natural or dietary compounds seems to focus on their potent anticancer activity combined with low toxicity and very few adverse side effects.
Obesity, Fitness & Wellness Week, 8/12/06
Greater Tea Consumption Related to Lower Risk of Various Cancers
A study conducted in Japan found that increased green tea consumption before and after breast cancer surgery was associated with lower recurrence of the cancers. Studies in China show that the more green tea participants drank, the less the risk of developing stomach cancer, esophageal cancer, prostate cancer, pancreatic cancer, and colon cancer.
Web MD April 28, 2009
Tea Associated with Lower Risks of Lung Cancer
Results from research showed that both smokers and non-smokers who did not drink green tea were 5 times more likely to develop lung cancer compared to those who drank at least one cup of green tea per day. Smokers who did not drink green tea at all were more than 12 times more likely to be diagnosed with lung cancer than those who drank at least one cup a day. Green tea’s cancer fight capabilities are due to its rich concentration of polyphenols, notably a catechin called epiqgallocatechin-3-gallate, or as it’s more commonly known as ECGC. The studies don’t change the fact that smoking is bad for your health, and tea should not be an excuse to continue smoking.
Bnet March 30, 2010
Endometrial Cancer May be Reduced by drinking Two Cups a Day Of Tea
After accounting for the different ways the studies measured tea drinking, the researchers found that an increase in tea consumption of two cups daily was associated with a 25-percent reduced risk of developing endometrial cancer. The association was significant for green tea but not for black tea.
Reuters, January 2010
Smokers & Non-Smokers alike have Lower Risks of Developing Lung Cancer with Green tea
[According to a new study from the American Association for Cancer Research], among smokers and non-smokers, those who did not drink green tea had a 5.16-fold increased risk of lung cancer compared with those who drank at least one cup of green tea per day. Among smokers, those who did not drink green tea at all had a 12.71-fold increased risk of lung cancer compared with those who drank at least one cup of green tea per day.
Science Daily, January 2010
Black and Oolong teas contain a Unique Compound that can kill cancer cells and reduce inflammation
Researchers from Rutgers University, NJ, studied theaflavin-2 (TF-2), a compound unique to black tea (and oolong), which has been shown to kill cancer cells, a process known as apoptosis. The TF-2 triggered cancer cell death, shrinking cancer cells within 3 hours of application. TF-2 appears to regulate or activate genes that kill cancer cells. In addition, it has the ability to suppress inflammatory enzymes and molecules. These results suggest that Theaflavin-2, a major component of black tea, has the capacity to help kill cancer cells through mechanisms involving both gene regulation and an anti-inflammatory effect.
Molecular nutrition & food research, February 2011