By Jane Hart, MD
Healthnotes Newswire (January 17, 2008)—Drinking green tea may reduce the risk of advanced prostate cancer, according to a new study. Green tea, made from the Camellia sinensis plant, contains catechins—antioxidant substances that may help stop cancer cell growth and prevent cancerous tumors from spreading.
A variety of factors may contribute to prostate cancer developing, including diet, lifestyle, and the environment. Incidence of prostate cancer is low in Asia, where green tea is a popular beverage, and the authors of the new study decided to evaluate green tea’s effects on prostate cancer development in Japanese men.
The authors looked at data from the Japan Public Health Center-based Prospective Study, which began in 1990 and included nearly 50,000 Japanese men. The men answered questions about how many cups of green tea they drank each day and for 14 years they were followed for a variety of health factors.
The study results, which were published in the American Journal of Epidemiology, found that men who drank five or more cups of green tea per day had less risk of developing advanced prostate cancer compared with men who drank less or no tea. The authors noted that information was not available on methods the men used to brew the tea, such as the infusion time or strength.
Drinking green tea was not associated with a decreased risk of localized prostate cancer, which is a less serious form of prostate cancer. The authors also noted that the men who drank greater amounts of green tea tended to be older, to smoke more, and to eat more miso soup, fruits, vegetables, and soy foods, and to drink less coffee.
Green tea has been the subject of many studies looking at its role in cancer prevention. Some studies have shown that green tea may prevent cancer while others have not. According to the study’s lead author, Norie Kurahashi from the National Cancer Center in Tokyo, Japan, the more green tea the men drank, the greater the protective effect. “Although this result is supported by many animal studies, further studies are required to confirm the preventive effects of green tea on prostate cancer, including well-designed clinical trials in humans.”
(Am J Epidmiol 2008;167:71–7)
Jane Hart, MD, board-certified in internal medicine, serves in a variety of professional roles including consultant, journalist, and educator. Dr. Hart, a Clinical Instructor at Case Medical School in Cleveland, Ohio, writes extensively about health and wellness and a variety of other topics for nationally recognized organizations, Web sites, and print publications. Sought out for her expertise in the areas of integrative and preventive medicine, she is frequently quoted by national and local media. Dr. Hart is a professional lecturer for healthcare professionals, consumers, and youth and is a regular corporate speaker.
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