Green Tea And Prostate Cancer
Prostate cancer is very scary thing and if you are a male over the age of 38 it should be on your radar. Prostate cancer is the most common form of non skin cancer in North America, it affects 1 in every 6 men. Age can be directly linked to the likelihood of being diagnosed with prostate cancer. Although only 1 in every 10,000 men under age of 40 will be diagnosed with prostate cancer, this rate rapidly rises to 1 in every 38 men for the ages of 40 to 59, and again 1 in every 15 for ages of 60 to 69. In fact, greater than 65% of all prostate cancer is diagnosed in men above the age of 65.
Green Tea however can help reduce your risk of being one of the unlucky that find themselves diagnosed with prostate cancer. Here are a few quick notes from the National Cancer Institute’s fact sheet:
The antioxidants found in tea–called catechins–may selectively inhibit the growth of cancer.- In lab studies using animals, catechins scavenged oxidants before cell damage occurred, reduced the number and size of tumors, and inhibited the growth of cancer cells.
- NCI researchers are investigating the therapeutic and preventive use of tea catechins against a variety of cancers.
Green Tea helps create a protective effect for advanced prostate cancer. This effect can be directly linked with the amount of green tea consumption, increasing intake is linked to reduced risk.
Effect of a prodrug of the green tea polyphenol (-)-epigallocatechin-3-gallate on the growth of androgen-independent prostate cancer in vivo.
Epigallocatechin-3-gallate (EGCG) is the major and most potent polyphenol compound of green tea that has been shown to have anticancer effects against various types of cancers. In this study, in addition to the EGCG compound, a synthetic derivative, the peracetate of EGCG (EGCG-P), was used to investigate the inhibitory effects on growth of androgen-independent prostate cancer in vivo. The advantage of EGCG-P is that it may act as a prodrug, leading to higher bioavailability than EGCG itself. The aim of our study was to compare the differences between EGCG and EGCG-P on their inhibitory effect on androgen-independent prostate cancer, CWR22R, xenograft model in nude mice. The mice were administrated daily with solvent dimethyl sulfoxide, EGCG, and EGCG-P separately through intraperitoneal injection for 20 days. Tumor volume and body weight of nude mice were recorded daily. Serum prostate-specific antigen (PSA) levels were also measured before and after the treatment. The effects of both EGCG and EGCG-P on tumor cell proliferation were assessed by immunohistochemical (IHC) method using antibodies against Ki-67 and proliferating cell nuclear antigen. The apoptotic effect was evaluated by IHC against B-cell non-Hodgkin lymphoma-2 and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay by in situ apoptosis detection kit. Moreover, the potential suppression of angiogenesis by EGCG and EGCG-P on prostate cancer was examined by IHC against CD31. Our results revealed that treatment of EGCG and EGCG-P compounds suppressed the growth of CWR22R xenografts without causing any detectable side effects in nude mice. The suppression of growth of the tumor was correlated with the decrease of serum PSA level together with the reduction in tumor angiogenesis and an increase in apoptosis on prostate cancer cells. The results showed that treatment of EGCG and EGCG-P inhibited tumor growth and angiogenesis while promoting apoptosis of the prostate cancer cells in vivo. Our results suggest that EGCG-P may be a more stable and useful compound for increasing the therapeutic anticancer effects in androgen-independent prostate cancer.
Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, HKSAR, China.
Lee SC, Chan WK, Lee TW, Lam WH, Wang X, Chan TH, Wong YC.
Green tea consumption and prostate cancer risk in Japanese men: a prospective study.
The incidence of prostate cancer is much lower in Asian than Western populations. Given that environmental factors such as dietary habits may play a major role in the causation of prostate cancer and the high consumption of green tea in Asian populations, this low incidence may be partly due to the effects of green tea. The JPHC Study (Japan Public Health Center-based Prospective Study) was established in 1990 for cohort I and in 1993 for cohort II. The subjects were 49,920 men aged 40-69 years who completed a questionnaire that included their green tea consumption habit at baseline and were followed until the end of 2004. During this time, 404 men were newly diagnosed with prostate cancer, of whom 114 had advanced cases, 271 were localized, and 19 were of an undetermined stage. Green tea was not associated with localized prostate cancer. However, consumption was associated with a dose-dependent decrease in the risk of advanced prostate cancer. The multivariate relative risk was 0.52 (95% confidence interval: 0.28, 0.96) for men drinking 5 or more cups/day compared with less than 1 cup/day (p(trend) = 0.01). Green tea may be associated with a decreased risk of advanced prostate cancer.
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
Kurahashi N, Sasazuki S, Iwasaki M, Inoue M, Tsugane S; JPHC Study Group.
Taxol synergizes with antioxidants in inhibiting hormal refractory prostate cancer cell growth.
Taxanes are chemotherapeutic agents commonly used to treat various carcinomas. Dietary antioxidants, such as vitamin E, green tea extracts, and isoflavones have been used against prostate cancer, and exhibit anticancer effects both in vitro and in vivo. We evaluated the combined effect of taxol (paclitaxel) with pyrrolidine dithiocarbamate, vitamin E, epigallocatechin gallate, and genistein in killing hormone-refractory prostate cancer cells. Those agents were tested on the hormone-refractory prostate cancer cell line PC-3, and the viability of the cells was determined using MTT {3 (4, 5-dimethylthiazo-2-yl)-2, 5-diphenyl tetrazolium} assay after drug treatment. PC-3 cells were sensitive to these drugs with 50% inhibitory concentrations of 0.1, 23, 220, 1122, and 260 muM, for taxol, pyrrolidine dithiocarbamate, epigallocatechin gallate, genistein, and vitamin E, respectively. Genistein, pyrrolidine dithiocarbamate, and epigallocatechin gallate showed synergistic cytotoxicity to PC-3 cells when combined with 0.01 muM taxol. Only high concentration of vitamin E showed a synergistic effect with this dose of taxol. Further study revealed that 3 combinations could induce sub-G1 phase of cell cycle, induce apoptosis, and increase caspase activity and decrease Bcl-2 expression simultaneously. In conclusion, in addition to vitamin E, incorporation of these antioxidants with taxan-based cytotoxic therapies offers encouraging strategies for combating hormone-refractory prostate cancers.
Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Ping SY, Hour TC, Lin SR, Yu DS.
Effects of the long-term ingestion of tea catechins on energy expenditure and dietary fat oxidation in healthy subjects.
The long-term ingestion of tea catechins has been reported to reduce body fat. The aim of this study was to investigate the effect of the long-term ingestion of tea catechins on postprandial energy expenditure and dietary fat oxidation. Twelve healthy men aged 27-48 years participated in the study. The subjects consumed 350 ml of a test beverage/day that contained either a high dose of catechin (592.9 mg) or a low dose of catechin (77.7 mg) for a period of 12 weeks. Respiratory analyses were conducted before and at 4, 8, and 12 weeks during the test period, in which oxygen consumption and the excretion of 13CO2 were monitored over 8 hr after a single ingestion of a test meal containing 13C labeled triglyceride. The excretion of 13CO2 in the high dose catechin group (the HC group) was significantly increased at 4 and 12 weeks of the test period compared to that for the low dose catechin group (the LC group) (p < 0.05), and this elevation persisted at 8.9% at week 0 to 12.9% at week 12. Dietary induced thermogenesis (DIT), defined as an increased energy expenditure from the fasting baseline for 8 hr after the single ingestion of a test meal, was significantly higher in the HC group at 8 and 12 weeks compared to that in the LC group (p < 0.05) with elevation to 90.3 kcal at week 12 from 51.4 kcal at week 0. In conclusion, enhanced dietary fat oxidation and an increased DIT may play an important role in the mechanism of the anti-obesity effect of tea catechins.
Journal Health Science. 51(2):248-252
Harada U., Chikama A., Saito S., Takase H., Nagao T., Hase T., Tokimitsu I.
