St. Patrick’s Day is this Sunday, March 17, 2013, and we were just trying to think of something “green” to share. Then, we received in our email a great article from our friends at the American Botanical Council about one of our favorite herbal remedies: Green Tea. While not Irish by any means (Green Tea is native to China), this herb has been a tasty and health-promoting elixir for generations all over the globe.
Doctors around the world recommend the consumption of Green Tea. Tea is, after all, the world’s most consumed beverage–second only to water. In fact, specifically some highly regarded oncologists suggest that Green Tea, in addition to providing antioxidants, metabolism support, and important vitamins and minerals, may play a role in the body’s defenses against ovarian and breast health concerns*. In fact, at the conclusion of each physiology class I took in college at the University of Chicago, our professor, an oncologist and leading authority on men’s and women’s health, would say, “Ladies and gentlemen, be sure to drink your green tea tonight.” We were excited to read the following excerpt from the American Botanical Council about studies performed on women in China with various types of cancer:
Epidemiological Assessment of Green Tea for Cancer Prevention
In vivo and in vitro studies have demonstrated that green tea (Camellia sinensis) has anticancer effects. The evidence in humans has been inconclusive. The variability in humans may have to do with tea-drinking practices (type, frequency, and quantity). The authors conducted 1 cohort study and 5 case-controlled studies that assessed whether green tea was associated with longer survival rates in patients with ovarian cancer and a lower risk of incidence of ovarian, breast, and colorectal cancers, and adult leukemia. Since all of the studies had similar methods, the purpose of the present study was to combine all of the data.
A total of 6,308 participants were in the 6 studies. The following four studies were conducted in southeast China from 2004-2005: a cohort study (n = 254) and a case-controlled study (n = 906) of women with ovarian cancer, a case-controlled study (n = 2,018) of women with breast cancer, and a case-controlled study (n = 217) of adults with leukemia. The following two studies were conducted in northeast China from 2008-2009: a case-controlled study (n = 1,233) of women with breast cancer, and another 3 parallel case-controlled studies (n = 1,680) on breast cancer, colorectal cancer, and adult leukemia. All studies included age- and gender-matched controls that did not have cancer. A validated questionnaire was used to collect information on demographics and lifestyle characteristics, tea consumption (patterns, preparation, type of tea, duration, frequency, and quantity of dried tea-leaf consumed), food consumption as assessed with a 100-item food frequency questionnaire, factors relevant to hormonal status, and family history of cancers.
A total of 55.1% of Chinese women in southeast China were tea drinkers compared with 26.1% of women in northeast China. Among the tea-drinkers in southeast China, 89% drank green tea only, 4.9% drank black tea only, 0.3% drank oolong tea only, and 5.8% drank both green and black tea. Among the tea-drinkers in northeast China, 61% drank green tea only, 9.3% drank black tea only, 1.2% drank oolong tea only, and 25.7% drank both green and black tea. An inverse association was observed between quantity, duration, and frequency of green tea consumed and risks of ovarian cancer, breast cancer, colorectal cancer, and adult leukemia. In particular, mortality from ovarian cancer decreased in those who consumed the highest quantity of green tea compared with non-tea-drinkers. In both Chinese populations, the apparent protective effects on breast cancer were of mostly the same magnitude, despite differences in tea usage.
The authors conclude that green tea consumption was consistently associated with a lower mortality from ovarian cancer, and with decreased risks of incidence of ovarian, breast, and colorectal cancers, and leukemia in China. The findings are consistent with data from in vivo and in vitro studies. The authors claim that their studies have been ranked as having a very high quality by a Cochrane review of green tea and cancer. A limitation of the study was that they did not determine whether diet, lifestyle, and hormonal status had any impact on the study outcomes.
—Heather S. Oliff, PhD
*There exists no claim that green tea can or will treat, cure, or prevent any disease.