BACKGROUND: Our previous case-control study revealed that the Japanese residents in Japan could be divided into those who are able to degrade daidzein, a soybean isoflavone, to equol and those without this ability, and that the incidence of prostate cancer is higher in the latter group. METHODS: We recently conducted a similar case-control study involving not only Japanese residents in Japan but also Korean residents in Korea. The incidence of prostate cancer in Korean residents is known to be close to that of Japanese residents in Japan. On the other hand, American residents in the United States have a markedly higher incidence of prostate cancer as compared to Japanese residents in Japan. RESULTS: The number of subjects was 295 in Japan (133 patients and 162 controls), 122 in Korea (61 patients and 61 controls) and 45 in the United States (24 patients and 21 controls). The percentage of equol producers among patients and controls was 29% and 46% in Japan (P = 0.004) and 30% and 59% in Korea (P = 0.001), respectively. The active isoflavone level was markedly lower and the percentage of equol producers was also lower (17% for patients and 14% for controls) for Americans as compared to the Japanese and Koreans. CONCLUSIONS: These results suggest that the ability of producing equol or equol itself is closely related to the lower incidence of prostate cancer. The results also suggest that a diet based on soybean isoflavones will be useful in preventing prostate cancer.
BACKGROUND: Our previous case-control study revealed that the Japanese residents in Japan could be divided into those who are able to degrade daidzein, a soybeanisoflavone, to equol and those without this ability, and that the incidence of prostate cancer is higher in the latter group. METHODS: We recently conducted a similar case-control study involving not only Japanese residents in Japan but also Korean residents in Korea. The incidence of prostate cancer in Korean residents is known to be close to that of Japanese residents in Japan. On the other hand, American residents in the United States have a markedly higher incidence of prostate cancer as compared to Japanese residents in Japan. RESULTS: The number of subjects was 295 in Japan (133 patients and 162 controls), 122 in Korea (61 patients and 61 controls) and 45 in the United States (24 patients and 21 controls). The percentage of equol producers among patients and controls was 29% and 46% in Japan (P = 0.004) and 30% and 59% in Korea (P = 0.001), respectively. The active isoflavone level was markedly lower and the percentage of equol producers was also lower (17% for patients and 14% for controls) for Americans as compared to the Japanese and Koreans. CONCLUSIONS: These results suggest that the ability of producing equol or equol itself is closely related to the lower incidence of prostate cancer. The results also suggest that a diet based on soybeanisoflavones will be useful in preventing prostate cancer.
Authors: Jennifer Ahn-Jarvis; Steven K Clinton; Kenneth M Riedl; Yael Vodovotz; Steven J Schwartz Journal: Food Funct Date: 2012-06-27 Impact factor: 5.396
Authors: Jennifer H Ahn-Jarvis; Steven K Clinton; Elizabeth M Grainger; Kenneth M Riedl; Steven J Schwartz; Mei-Ling T Lee; Raul Cruz-Cano; Gregory S Young; Gregory B Lesinski; Yael Vodovotz Journal: Cancer Prev Res (Phila) Date: 2015-08-14
Authors: William R Wikoff; Andrew T Anfora; Jun Liu; Peter G Schultz; Scott A Lesley; Eric C Peters; Gary Siuzdak Journal: Proc Natl Acad Sci U S A Date: 2009-02-20 Impact factor: 11.205
Authors: M Tanaka; K Fujimoto; Y Chihara; K Torimoto; T Yoneda; N Tanaka; A Hirayama; N Miyanaga; H Akaza; Y Hirao Journal: Prostate Cancer Prostatic Dis Date: 2009-07-14 Impact factor: 5.554