To Soy or Not to Soy

Posted on Jul 1, 2013

Most food is straightforward. It’s either good for you or not. But when it comes to soy, everything I read seems to say something different. Some people praise soy. They say it’s a wonderful vegetable protein that has been proven to lower the risk of heart disease, cholesterol, and cancer. Japanese women eat a lot of soy, after all, and they have much lower rates of breast cancer than westerners. Yet other sources say that soy actually increases your risk of cancer, can cause infertility, and developmental problems in children. Is anyone else really confused?

After reading a lot of various articles over the past year, I’ve figured a few things out:

First of all, there are two different kinds of soy.

Unfermented Soy

This includes tofu, soymilk, soybeans and the various forms of soy powder found in a lot of processed foods. Unfermented soy contains phytochemicals, which are used to protect the plant from predators. During the fermentation process, these phytochemicals are removed. The phytochemicals in unfermented soy, however, can cause a breakdown of your immune system. Unfermented soy also contains isoflavones, a.ka. plant estrogens. The bottom line is that scientists don’t know yet what these estrogens do to our bodies. And as for the fact that Japanese women have lower risks of cancer, well, there are so many other parts of their daily lifestyles that are vastly different than the typical American’s that it’s hard to say that soy, and only soy, is the reason.

Fermented Soy

This includes soy sauce, miso, tempeh and natto. This soy is actually good for you, and that’s something all scientists and nutritionists can agree on. Why? The fermentation process lowers the levels of isoflavones and phytochemicals.

So should you avoid unfermented soy? From what I’ve read (and I’m certainly not an expert), women with a family history of breast cancer should avoid it, men hoping to father children should limit it, and parents should be very cautious feeding it to children. Personally, I’ve never been a big fan of tofu, so avoiding that is easy for me. Same with soymilk. And I try not to buy anything that has soybeans or soy powder in it. As for the fermented soys, thank goodness soy sauce is on that list, for I really can’t imagine life without it. And I have yet to cook with miso or tempeh, but plan on incorporating that into recipes soon.

Here’s some further reading, for anyone who’s interested: