Soy beans in and of themselves can provide a nice, healthy dose of wholesome vitamins, minerals, fiber and other nutritionally rich components. While they do supply a bit of what’s called phytoestrogenic effect, which means they have some naturally active components that mimic the effects of estrogen in the body, they have a complete nutritional profile because they are the whole, unprocessed and unadulterated form of a vegetable.
If you imagine what most processed soy products are, they are very different from the original soy bean, and they are highly processed. The problem is, they are also still estrogenic in their effects. So you basically strip out all the other nutritional benefits that raw soy has, and you still have the fact that these products have estrogenic effects, and that is something that’s not so healthy for your breasts.
The more body fat you have, the more estrogen that you have circulating in your body since estrogen tends to embed itself in fatty tissues. This can also explain why one of the fattiest areas on a woman’s body, and also a part that tends to be extremely sensitive to hormone fluctuations (think how tender your breasts are during your period and pregnancy, when estrogen is surging and receding), is prone to have abnormal cell growth that results in cancer.
Because processed soy causes increases in these synthetic/alternative estrogens in the body, and these estrogens tend to store in the fatty tissues of the body more than other places, and the fact that breast cancer is often driven by estrogens in part, it is prudent to avoid processed soy products.
They can be really easy to eat too much of as well, especially if you are a person who does not eat meat or other forms of protein. If you eat them, be sure to eat them in moderation.
Instead of using them as a source of alternative protein, look for other sources, like fish, various types of nuts and seeds, quinoa, which supplies a lot of the amino acids you might be missing from a meat free diet, and other plant based sources of protein. Or, dairy can supply a good type of protein as well as long as it’s not too high in fat.