Soy Protein Isolate
Soy protein isolate is a problem for me.
I am a dedicated vegan since 1996, and vegetarian since 1989. I do have concerns about soy, on two fronts. First, I have read that soy products (as well as certain other foods such as cruciferous vegetables) can inhibit iodine absorption in the body and therefore create thyroid problems. However, I have also read that this problem of preventing iodine absorption can only happen with uncooked foods, and normally one would not be eating uncooked soy. I do have an underactive thyroid for which I have to take medication, so I do have concerns.
Second, and most importantly for me, many forms of soy I find very difficult to digest, especially soy protein isolate, soynuts, and edamame. These cause me intestinal cramping and irritation (I have this same problem with nutritional yeast.) I am wary of soy flour and soy oil as well on this basis. I have also read that soy oil is considered toxic in traditional Chinese medicine.
This is unfortunate because so many foods now have one or more of these ingredients, because they are so readily available and cheap, I think, especially soy protein isolate. I do not seem to have problems with tofu or tempeh, however, and continue to eat those in moderation, but not everyday.
I do wish that soy were not so ubiquitous, for several reasons. Based on my thyroid concerns, my digestive difficulty with many forms of soy, knowing that other people have similar digestive troubles with it, and the serious environmental ramifications of soy as a crop, I think it is very, very unfortunate that so many foods, as a matter of routine, have soy as an ingredient.
It's like putting too many eggs in one basket, so to speak, to use a non-vegan metaphor. All in all, this heavy reliance on soy does not seem balanced to me.
And to say a little more about the serious environmental ramifications: I have actually heard people use that as an excuse to put down vegetarians and vegans-- as though, well, if you're a vegetarian, of course you eat soy, and therefore you are harming the planet by stripping the forests and stripping the topsoils. I have a not-very-close friend who is a soil scientist who has not only said this to me, but also makes this point in public lectures he gives. This guy used to be a vegetarian, but now he uses the environmental harms of soy as an excuse not to be a vegetarian.
Again, if there hadn't been so much hype about soy being "the" vegetarian food, and if so many food products hadn't started loading up on soy ingredients, and if there were more variety in the vegetarian and vegan-themed foods out there (i.e., more veg friendly options out there that don't have soy in them), I think it would very much help the vegetarian and vegan cause by not limiting its image and reality to soy and its pitfalls.