Prostate cancer is defined as ''advanced'' when it spreads outside the prostate gland. Dietary intake of isoflavones was linked with an elevated risk of advanced prostate cancer.
No statistically significant associations were observed between the intake of isoflavones and non-advanced prostate cancer. Isoflavones are a type of phytoestrogen, a family of estrogen-like compounds found in plants, and are found in soybeans, kudzu root, and American groundnuts.
‘Prostate cancer is often slow-growing and symptoms may not occur for many year, but dietary intake of isoflavones can increase the risk.’
During a median follow up of 11.5 years, 2598 cases of prostate cancer (including 287 advanced cases) were identified among 27,004 men in the intervention arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Dietary intake was assessed with a food frequency questionnaire.
"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."