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Soy protein BAD, I don't think so.
Recently, an article was written by a certain Net Magazine, claiming that soy protein was a "Bad" Protein to use if you were a bodybuilder looking to add lean muscle mass. The article concluded with the use of research studies, that soy proteins' phytoestorgens actually lowered testosterone production in animal studies. Hence lower testosterone levels, higher estrogen levels, no muscle gains.
But of course there are always two sides to the story, and I think I have a better case, jury listen up!!!
I would have to disagree, and nutritional experts agree, that soy protein is an excellent protein to use if you're a bodybuilder using the protein to gain muscle mass. Here are a bunch of reasons.
1) A study found that soy protein isolate (daidzein) may have a gender specific normalizing effect on sex-hormone prduction. Male lab animals experienced greater testosterone and growth-hormone excretion as well as muscle growth" This contradicts the study that found that genestein decreased testosterone serum.
2) Another study found that soy may be actually antiestrogenic. . They may also act as antiestrogens by competing for the binding sites of estrogen receptors or the active site of the estrogen biosynthesizing and metabolizing enzymes, such as aromatase and estrogen-specific 17 beta-hydroxysteroid oxidoreductase (type 1).
3) Probably the best research study contracting the one used by the author of "The bad protein" is this.
The phytoestrogens are only found in raw soy products. Not soy protein isolates, which are used as protein supplements for bodybuilders.
"There are very little data on effects of phytoestrogens in males. Estrogenic effects in wildlife have been described but the evidence for the role of phytoestrogens is indirect and seen under conditions of excessive exposure."
And what is most interesting about this study is that it was conducted by one of the same researchers at the same univeristy as the study that found genistein lowered testoserone serum levels. This researcher concluded that even though he found genestein has estrogenic effects, it really cant be concluded because of the above statement in his other reasearch findings. Hence, he found soy to be estrogenic, but it really cant be "hard" evidence because there is not enough proof and it involves ridiculous conditions.
See what I mean by two sides to every story..
Positive Benefits of soy
1) The amino acid profile of soy is excellent. If you don't know by now the Glutamic Acid level is higher than whey. Why? Mainly because it is a plant protein and not dairy.
2) Soy has been proven to lower heart disease risks and cancer. Now there are about a million studies on this statement. I not going to quote any.
3) Soy protein actually improves kidney function.
4) When soy was combined with a carbohydrate in comparison with casein. Lower bodyfat gains were observed.
1) Dr. Mauro Di Pasquale , probably one of the greatest sports nutritonist authors to ever live. (and trust me on this one) quoted in Muscle Media Magazine. "I use a combination of soy, casein, and whey protein that I make up myself from three different products, each one containing on of the protein isolates in quality form"