A multivariate analysis revealed that there was an increased risk of prostate cancer associated with an intake of total isoflavones (hazard ratio [HR], 1.91; 95% CI, 1.25-2.92), genistein (HR, 1.51, 95% CI, 1.02-2.22), daidzein (HR, 1.80; 95% CI, 1.18-2.75), and glycitein (HR, 1.67; 95% CI, 1.15-2.43) (P-trend for all associations less than 0.05). There were, however, no statistically significant associations between total isoflavone or phytoestrogen intake and prostate cancer.
The results demonstrate that a higher intake of isoflavones may increase the risk of advanced prostate cancer. The authors concluded, “[t]he findings of the present study need to be confirmed in a more prospective cohort or nested case-control studies to be conducted by measuring both dietary intake of phytoestrogens and their biomarkers among populations with diverse dietary habits.”
Reger MK, Zollinger TW, Liu Z, Jones JF, Zhang J. Dietary intake of isoflavones and coumestrol and the risk of prostate cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial [published online November 8, 2017]. Inter J Cancer. doi: 10.1002/ijc.31095