[Prostate cancer prevention].

Environmental factors, mainly diet, play an important role in the development of prostate cancer. A previous study identified fat and calcium as risk factors, and lycopene, selenium, soy isoflavone, and vitamin E as preventive factors for the development of prostate cancer. However, many previous studies were observational or in vitro/in vivo based, and enough evidence in a large-scale randomized study has not been provided. In the study of food, not only the intake but also the metabolism is important. For soy isoflavone, analysis of enterobacterial flora concerned with its metabolism to equol is in progress.