Soy is widely known in health circles as pro-estrogenic and feminizing and men are recommended to avoid it. If that’s actually the case, can anyone explain why serum estrogen levels actually decrease in soy-supplemented groups in studies in both men and women? And why is there an inverse relationship between hormone dependent cancers such as breast and prostate cancer (I suppose all cancers are hormone dependent) and soy consumption? Here are just some of the studies I’m talking about:

https://www.ncbi.nlm.nih.gov/pubmed/8770469 – 36-oz of daily soymilk consumption for a month significantly decreased serum 17 beta-estradiol levels in premenopausal women.

https://www.ncbi.nlm.nih.gov/pubmed/9839524 – Estrone and estradiol levels were decreased by 23% and 27% at the end of the study in the soy milk supplemented group in Japanese women. The change in estrone and estradiol levels was minor in the control, non-soy group.

https://www.ncbi.nlm.nih.gov/pubmed/11303585 – Serum estrone concentrations decreased in the soy-supplemented group in Japanese men. There was no change in testosterone levels in both the soy group and the control group.

Is it that the estrogen circulation in blood decreases from soy but estrogen level inside the cell increases? Is that why soy is so widely considered as ‘estrogenic’?