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Originally Posted by Bob Smith For the past few years, I and many others were under the belief that soy protein is an inferior protein source, it raises estrogen levels (or reduces test levels) in men, and so on. Can you give us a quick overview as to whether those beliefs are true or bunk. Bottom line: is soy protein a good source for BBers? |
I haven't made up my mind, data is all over the map.
As far as protein quality, i don't think normal soy protein is very good. At least one or two studies show that it gets used up by the splanchnic area (gut and intestine) and isn't as effective at promoting protein synthesis. Most likely an issue of the amino acid profile. Commercial soy powders (i.e. Twinlab's old Vege Fuel) usually have the limiting amino acids added and might not have that problem.
As far as the estrogen issue, fuck if I know. If I had to guess at it now, I'd say that the phytoestrogens (which are weak estrogens relative to what's found in the body) might be beneficial for women (competitive inhibition of estrogen receptor leading to overall LESS estrogenic activity) and maybe bad for men. Whether commercial soy protein powders contain much in the way of phytoestrogens, I don't know.
how's that for a fucking useless answer?
I know Brink is a big fan of soy but I suspect he's referring to commercially made soy isolates which are probably a different animal than soy foods. Considering all the readily available protein sources that are out there (meat, milk, whey, eggs, etc), why not just use those and avoid the whole issue?
Lyle