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SoyCaP: Soy and Prostate Cancer Prevention

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Annual summary 24 Oct 2005-23 Oct 2006

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The main objective of this project is to evaluate the effects of soy phytoestrogens on reproductive hormones and prostate tissue markers of cell proliferation and androgen action in men at high risk of prostate cancer. The hypothesis is that alteration of endogenous hormones is a mechanism by which soy phytoestrogens prevent prostate cancer. A randomized parallel arm study is being performed in which 58 men at high risk of prostate cancer were randomized to receive one of three dietary supplements for six months 1 soy protein isolate containing isoflavones 2 isoflavone-poor soy powder or 3 isoflavone-free milk powder. Urine and blood is collected at 0 3 and 6 mc for evaluation of serum hormones and prostate specific antigen as well as urinary estrogen and phytoestrogen metabolites. At 0 and 12 mc prostate biopsies a performed to evaluate prostate tissue expression of apoptosis Sax 501-2 proliferation PONA and androgen receptor density. We found isoflavone-rich soy protein isolate suppressed androgen receptor density increased urinary estrogen excretion and increased the 216-OH estrogen ratio in the urine. We also observed a trend toward a lower rate of prostate cancer in the men in the soy groups compared to the men in the milk group

Subject Categories:

  • Anatomy and Physiology
  • Medicine and Medical Research
  • Food, Food Service and Nutrition

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