When soybeans are ground up, dehydrated, dehulled, and defatted, you end up with soy flour (50% protein), soy concentrate (65-70% protein), and soy isolate (90% protein). If you walk into a supplement store or browse the web for ‘soy protein powder,’ chances are that what you’ll get is soy isolate, the most refined type of soy protein.
Soy protein is very popular with vegans and vegetarians because of its mild taste, its frequent marketing as a ‘health’ or ‘diet food,’ and the fact that it contains all essential amino acids. It’s frequently used as a meat substitute too, and included in protein powders, protein foods, and protein drinks as a way to bump up their protein content (more on this below).
If you grab your tub of whey, casein, or vegan protein powder and you turn it over, it’s very likely that you’ll find ‘soy lecithin‘ (or E322) as one of its ingredients. Soy lecithin is an emulsifier. A very cheap emulsifier. What it does is ensure that your protein powder, when mixed with water or milk, doesn’t separate, clump up, and float all the way to the top.
Why I Said No to Soy
I don’t like or use soy protein. I don’t ever recommend it to Pow readers either. Last time I bought a tub of soy protein, yeeeeears ago now, I ended up drop-kicking it into the trash three-fourths of the way full. That’s because, right after buying it, I spent the rest of the week doing research to learn all I could about soy isolate and its impact on our bodies, both actual and conjectured.
What I found was an extremely polemic discussion, lead (quite forcibly!) by people with vested interests, e.g. groups from within the soy industry and authors of anti-soy articles and books. The former were saying “Soy is healthy! Eat more of it! It’ll save you from XYZ diseases!” while the latter screamed “TOXIC, TOXIC!”
The more I read though, the more I concluded that the following four points held quite a bit of ground. Enough, at least, to turn me off soy completely:
1) Soy protein is commonly derived from genetically modified (GM) soy.
2) Soy protein contains phytoestrogens, which have been argued to disrupt endocrine function by mimicking the physiological effects of estrogen.
3) Soybeans can be goitrogenic meaning they can depress thyroid function.
4) Soy protein is of low quality so it’s extremely cheap compared do other sources of protein. That’s why companies regularly use it as a bulk ingredient: to push up their products’ protein content without investing in more expensive protein powders like whey, casein, and/or any other veggie proteins.
The take home message for me, and consequently the message I’d like to send over to you, is this: eat the best food that you possibly can. No food in particular will kill you in moderation (well, not unless you have an acute allergy!) Soy won’t be the end of you. Remember what I mentioned in my Sweeteners Post: ‘the poison is in the dose’!
That being said…
Why bother eating foods we can extremely easily substitute with better ones? Why not treat our bodies to the BEST possible foods? Why bog ourselves down with ingredients that don’t make us 100% comfortable? Why buy powders, foods, and drinks that claim to be one thing (‘full of high-quality protein’!) when what they end up containing is another (e.g. soy).
Remember: Always Read the Label
When you go out and choose a protein powder, protein food, or drink, I urge you to look out for whether or not it contains soy. A lot of them don’t actually mention it explicitly. You may buy a protein powder marketed as featuring whey, casein, pea, hemp, or rice protein only to then find out, upon reading its ingredients’ label, that its second or third ingredient is soy protein. The same goes for protein bars and protein foods. So pay attention to ingredients’ labels. ALWAYS. And avoid ‘premium’ brands that don’t mention soy in their description yet feature it as a primary ingredient. Obviously soy lecithin isn’t as big of a deal since it’s included in very small quantities. But soy protein as the first or second ingredient of the protein powder, food, or drink that you’re buying? Bah. There are far better options out there ;-)