Does soy protein lower testosterone?

I think it does. I became familiar with soy products back in the 60's as I lived in Hawaii and was exposed to Asian cultures there. Naturally, I came to regard dishes prepared with miso, tamari, natto and tofu as the best way to eat soy products.

I also came to regard new age food faddists as rather odd. It was strange to see people showing signs of malnutrition congratulating one another on their health. I am not talking about people who make a point of fully understanding their nutritional needs, but faddists. I know folks who went completely vegan, but took it too far. (Don't get me wrong. I regard a vegan diet as an excellent extended fast allowing the body to recover from the diseases of excess arising from the typical American diet.) After they had their first round of "detoxes" they felt fine. A year and a half later, they thought they were undergoing a deeper "detox" when it was clear that they were showing symptoms of protein malnutrition. But I digress...

There appears to be some evidence that moderate to large amounts of processed non-fermented soy derivatives have adverse hormone-related effects on the body. This is nasty, since soy is touted as "natural." A woman seems to think her PMS got worse. Another fellow is on a rant about how soy is being foisted on the American public.

Without going into it in depth, I would say that dietary inclusion of fermented soy products in small amounts does no harm. Conversely, consumption of moderate to large quantities of non-fermented soy-derived food products appears to have an adverse effect. Bodybuilder and doctor Kaayla T. Daniel, PhD explains why.