American Journal of Epidemiology Advance Access originally published online on May 16, 2008
American Journal of Epidemiology 2008 168(1):119; doi:10.1093/aje/kwn126
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LETTERS TO THE EDITOR |
RE: "GREEN TEA CONSUMPTION AND PROSTATE CANCER RISK IN JAPANESE MEN: A PROSPECTIVE STUDY"
From the Department of Family Medicine, University of Illinois at Chicago, Chicago, IL
(e-mail: shailendrakapoor{at}yahoo.com)
I read with great interest the recent Journal article by Kurahashi et al. (1) linking green tea with prostate cancer prevention in Japanese males. Recent studies indicate that green tea (Camellia sinensis) may also have a major role to play in the chemoprevention of other systemic malignancies.
For instance, polyphenols found in green tea have been shown to prevent the formation of aberrant crypt foci in the colon, which are precursors of colorectal cancer (2). Yang et al. (3), in a recent study conducted among Chinese women, reported that the relative risk of colorectal cancer was 0.63 for women who drank green tea regularly in comparison to women who did not drink green tea regularly. Thus, green tea intake can significantly decrease the risk of colorectal cancer. Polyphenols found in green tea have also been shown to be potent inhibitors of the carcinogenic effects of ultraviolet light on the skin (4). Studies indicate that green tea can very effectively inhibit the formation of mixed cutaneous tumors as well as cutaneous squamous cell carcinomas. Qin et al. (5), in a recent study, have also shown that epigallocatechin-3-gallate found in green tea enhances apoptosis in bladder cancer cells (5). Epigallocatechin-3-gallate also inhibits the expression of amyloid precursor protein and thus decreases the risk of oral squamous cell carcinomas (6). Zhang et al. (7), in another recent study, have reported that green tea consumption is associated with a significant decline in the risk of breast cancer. In their study, the authors reported that the odds ratio for developing breast cancer in women who drank 500–749 g of green tea a year was 0.59.
Besides these potent anticarcinogenic effects, green tea has also been shown to prevent hypertension as well as diminish end-organ damage secondary to hypertension (8). Clearly, the beneficial effects of green tea extend beyond prostate cancer. There is an urgent need to increase awareness about green tea and to incorporate it into Western cultures so as to fully benefit from its anticarcinogenic properties.
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ACKNOWLEDGMENTS |
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Conflict of interest: none declared.
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References |
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 TOP References |
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- Kurahashi N, Sasazuki S, Iwasaki M, et al. Green tea consumption and prostate cancer risk in Japanese men: a prospective study. Am J Epidemiol (2008) 167:71–7.
[Abstract/Free Full Text] - Xiao H, Hao X, Simi B, et al. Green tea polyphenols inhibit colorectal aberrant crypt foci (ACF) formation and prevent oncogenic changes in dysplastic ACF in azoxymethane-treated F344 rats. Carcinogenesis (2008) 29:113–19.
[Abstract/Free Full Text] - Yang G, Shu XO, Li H, et al. Prospective cohort study of green tea consumption and colorectal cancer risk in women. Cancer Epidemiol Biomarkers Prev (2007) 16:1219–23.
[Abstract/Free Full Text] - Yusuf N, Irby C, Katiyar SK, et al. Photoprotective effects of green tea polyphenols. Photodermatol Photoimmunol Photomed (2007) 23:48–56.[CrossRef][Web of Science][Medline]
- Qin J, Xie LP, Zheng XY, et al. A component of green tea, (-)-epigallocatechin-3-gallate, promotes apoptosis in T24 human bladder cancer cells via modulation of the PI3K/Akt pathway and Bcl-2 family proteins. Biochem Biophys Res Commun (2007) 354:852–7.[CrossRef][Web of Science][Medline]
- Ko SY, Chang KW, Lin SC, et al. The repressive effect of green tea ingredients on amyloid precursor protein (APP) expression in oral carcinoma cells in vitro and in vivo. Cancer Lett (2007) 245:81–9.[CrossRef][Web of Science][Medline]
- Zhang M, Holman CD, Huang JP, et al. Green tea and the prevention of breast cancer: a case-control study in Southeast China. Carcinogenesis (2007) 28:1074–8.
[Abstract/Free Full Text] - Antonello M, Montemurro D, Bolognesi M, et al. Prevention of hypertension, cardiovascular damage and endothelial dysfunction with green tea extracts. Am J Hypertens (2007) 20:1321–8.[CrossRef][Web of Science][Medline]
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