Phytoestrogens are the non-steroidal active compounds in soy which give it its therapeutic properties. In the absence of endogenous estrogen, such as in the menopausal state, phytoestrogens can bind to the estrogen receptors and increase estrogen activity. BUT WHEN ESTROGEN LEVELS ARE HIGH THE PHYTOESTROGENS COMPETE WITH ENDOGENOUS ESTROGENS FOR THE ESTROGEN RECEPTOR SITES AND CAUSE AND OVERALL DECREASE IN ESTROGEN ACTIVITY.
Never saw anyone post anything like this and i happened to come across it today.
Citation: Glissen, J., Crawford, R. The clinical applications of ginko biloba, st. john's wart, saw palmetto and soy. The Nurse Practitioner 1999; 24 (6): 28-47