Eating diets rich in isoflavones increases the risk of advanced prostate cancer, says a study published in the International Journal of Cancer. However, isoflavones, which are a type of phytoestrogen found in large amounts in soybeans, didn't appear to increase the risk for developing non-advanced prostate cancer.

"Prostate cancer is a major cancer in Western countries and its incidence rate has been remarkably increasing in Asian countries during the last several decades," said senior author Dr. Jianjun Zhang, of the Indiana University Fairbanks School of Public Health.

"Our study offers novel evidence that dietary intake of isoflavones has different effects on advanced and non-advanced prostate cancer. This observation is important for understanding the etiology and prevention of prostate cancer but needs to be confirmed in more epidemiologic studies among populations with diverse dietary habits."

Numerous other studies have found that soy products actually reduce the risk for prostate cancer, but Zhang's study found soy increases the risk of a prostate cancer becoming advanced. Advanced prostate cancer means it has spread outside of the prostate to lymph nodes, bones, or other parts of the body. The five-year survival rate is only 29 percent.

Several studies have found that soy has negative effects on a man's reproductive system. A study earlier this year found that natural chemicals in soy may lower a man's chances of fathering a child. Spanish researchers found that a vegetarian diet high in soy products such as tofu and soy milk reduced the numbers and mobility of sperm, as well as increased the number with missing chromosomes. They believe the culprit is phytoestrogens in tofu, which mimic female hormones.

Although soy products may increase the odds of advanced prostate cancer, other foods are protective. An Italian study found that men who drank three cups of Italian-style coffee every day reduced their risk of prostate cancer by 53 percent. The coffee was prepared "Italian Style" using high pressure, high water temperature, and no filters. Researchers believe the benefit was probably due to the caffeine, but could also be increased because of the method of preparation which could lead to a higher concentration of helpful bioactive substances.

According to cancer.org, about one American man in seven will be diagnosed with cancer during his lifetime. In the U.S, prostate cancer is the third leading cause of death in men.