You know, I read A LOT of medical literature. Finding negative health effects of soy is actually quite difficult.
The evidence on the health of soy is overwhelmingly positive. There are still oncologists telling their breast cancer patients to avoid soy, despite the fact that it DOUBLES survival rates. Of course, we are talking about organic (i.e. non-GMO) and unprocessed (no “soy burgers” or “soy dogs” or “TVP”).
The other complicating factor that needs to be understood about soy is that, for the full benefits to be obtained, we need to have the right blend of good bacteria in our gut to convert the isoflavones to their aglycone form, thus getting the most benefits from the soy intake. This particular small study further confirms this, finding that the ability of soy to lower cholesterol was greater when prebiotics (fiber that can aid the growth of healthy bacteria) were added into the diet.