Prostate cancer is the 4th most common type of cancer worldwidehowever, the incidence of the disease varies geographically.
The United States has one of the highest rates of prostate cancer. According to the American Cancer Society, more than 240,000 men are diagnosed with the disease every year, which translates into more than 2 million prostate cancer survivors currently living in the U.S.
Asian countries, on the other hand, have significantly lower rates of prostate cancer.
The difference in the rates of cancer in the U.S. and Asian countries are due to a number of factors, including screening, genetics and environmental influences.
Epidemiologic studies have tried to isolate the impact of genetics and environment by examining the incidence of prostate cancer between men of Chinese descent living in either China or the U.S.
Interestingly, those living in the U.S. had a ten-fold higher incidence of cancer. Similar studies have found identical trends in Japanese men, which suggests a significant role of environment in the onset of the disease.
Diet is one factor which has been presumed to pay a key role in reducing the disease rate in Asian countries. In particular, it has been hypothesized that the high intake of soy in these countries may be responsible for the lower risk of prostate cancer.
Soy is a unique dietary source of isoflavones, such as genistein and daidzein. These compounds act like the hormone estrogen in humans and have been found to inhibit tumor cell growth.
Genistein, in particular, has been targeted as a potent anti-cancer compound. In cell culture studies, researchers have shown that genistein inhibits prostate cancer cell growth and also induces cellular death. Additionally, studies have demonstrated that genistein enhances the ability of radiation to kill prostate cancer cells.
Similarly, rodents fed a diet high in soy were less likely to develop tumors and those that did develop prostate cancer, tended to have less aggressive disease. Specifically, these findings were attributed to a substantial increase in apoptosis, cell death, and decrease in tumor vessel development.
Read the original here:
High soy diet reduces risk of prostate cancer
