Soy's action a phytoestrogen is extremely complex. Many countries where soy is commonly eaten actually have lower rates of hormone related cancers. Soy is a weaker phytoestrogen than our estrogen yet binds to the same receptors. Some doctors go as far as to recommend soy to block the more problematic estrogen from binding to cancerous cells. There is one molecule of soy that actually blocks a cancer pathway of growth, too.
It doesn't make sense that places where soy is heavily consumed don't have as many hormonal cancers while it is closely linked to other hormonal problems like beast growth and earlier menses here in the US. Asian countries don't seem to have those problems at the same scale, either. It is hotly debated in oncology circles. People get vicious.
I like tempeh, so I eat it some, but I would never use soybean oil or eat soy regularly, either.
There are many phytoestrogens, though. Soy is just the most studied. Red Clover is used in several herbal cancer remedies but it has phytoestrogens.
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