interesting study:

Cancer Epidemiol Biomarkers Prev. 2007 Apr;16(4):829-33. Links
Clinical and biological activity of soy protein powder supplementation in healthy male volunteers.

* Goodin S,
* Shen F,
* Shih WJ,
* Dave N,
* Kane MP,
* Medina P,
* Lambert GH,
* Aisner J,
* Gallo M,
* DiPaola RS.

Department of Medicine, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, New Brunswick, NJ 08903-2681, USA. goodin@umdnj.edu
PURPOSE: To determine if a commonly used soy protein supplement exhibits biological activity in vivo and in vitro, we evaluated an over-the-counter soy protein powder supplement using blood from healthy male volunteers and in an estrogen receptor in vitro assay. SUBJECTS AND METHODS: We recruited healthy male volunteers 18 years of age or older that were in good health. Treatment consisted of consuming two scoops (56 g) of pure soy protein powder (Puritan's Pride, Oakdale, NY) daily for 28 days. Serum testosterone and luteinizing hormone (LH) levels were collected on days -7, 0, 14, and 28 of therapy, and day 42. A reporter estrogen receptor (ER) assay was used to determine the effect on ER-beta and ER-alpha in vitro. RESULTS: Twelve subjects were enrolled with a mean age of 32.25 years (range 25 to 47). Serum testosterone decreased 19%(+/-22%) during the 4-week use of soy protein powder (P = 0.021) and increased within 2 weeks after we discontinued soy protein powder. Serum LH concentrations decreased during the 4-week use of soy protein powder then increased within 2 weeks after we stopped the soy protein powder, but the changes did not reach statistical significance (P = 0.20). Soy protein powder was found to induce agonist activity to ER-beta using a reporter estrogen receptor assay in yeast. CONCLUSION: Soy protein powder decreases serum testosterone levels in healthy men and acts as an ER-beta agonist; the significance of this biological effect with respect to cancer prevention needs further study.
PMID: 17416779 [PubMed - in process]

I find this study a little strange? I am not a giant "touter" of Soy Protein, however, I am a firm beleiver that Soy Protein ISOLATE definetly has a good place in the bioavailable protein spectrum. Was this particular study done with "Soy Protein" (which typically is in the form of Concentrate) or "Soy Protein Isolate"?? The difference could be very great.

Soy Isolates are very stripped down and in its purest form. In the process, the estrogenic compounds and isoflavones are eradicated and what you are left with is 98%-99% protein per gram of substance.

There is a TON of scientific evidence out there showing Soy Protein Isolate having a spectrum that is Superior to Whey isolates when considering naturally occurring Glutamine and the Branch Chain Amino group. It even has a much slower absorption rate in comparison to the VERY fast digestion/gastric emptying of Whey Isolates in particular. The only real fallback I see to Soy Isolates are the lack of sulphur containing amino acids - methionine and cystein (i think), which are essential aminos. That being said, Whey concentrates AND Whey Isolates don't exactly have a knockout amount of the sulphur containing aminos either.... hmmmmm, something is amiss....

Anyways..... BEVERLY RULES!!!

Thanks Dr.!

I have a major problem with soy. Many products are now containing soy protein, products that did not have it 5 years ago. ARRRG.

Although it has great amino profiles, the side effects seem to outWHEY the benefits.

I have to agree with you Frank. I think soy protein has a great place in assisting with certain health problems/concerns and has some general health benefits, but unfortunately there still isn’t enough evidence that shows that it produces real world bodybuilding/body compostion changing results (building muscle and losing fat).

Great post Doc!

There are much better and complete proteins avaialable...hydrsolated whey, whey isolate, egg, etc.

It is no Surprise that Soy is showing up more often...

With the cost of the cheap wheys (wpc) going up like they have it is no surprise that companies are looking for lower cost alternative protein sources. I even saw an add in one magazine touting a product as NOT being milk derived and coming from vegetables (protein source is from BuckWheat). They sited reduce gastro-intestinal distress (gas, diarhea, cramps, all the stuff that comes from cheap wpc) as one of the reasons it is better. Of course their Buckwheat protein factions are patented so it must be great.


Are they kidding??? What is scary is the general gym rat meat head poplulation is going to scarf it up thinking it is something great.

Here is how high prices have gone in the cheap 5lb bucket world. We used to carry one of the large companies 5lb bucket at my club. Wholesale cost to us was about $20.00. Since the first of the year wholesale cost has almost doubled...

The good news is that we are selling even more Beverly.

Ray

That is true. The cost of Dairy all together has increased upwards of 30%?? The bigger companies can't make the same profit from that kinda increase in bulk Whey.

Ten years ago when Whey first hit, there wasn't a "better" protein in the universe (so they claimed). Sure whey is good, but before the Whey hit the market, all the companies were pushing eggs!! What happened you ask? The price of eggs went up and all of a sudden.... BOOM ... Whey hits the market as the next Sustenon-Growth-Ultimate-Universal-Protein!! All of a sudden, if you were still taking Egg protiens, then you weren't cutting edge....

News Flash... EGGS ARE STILL THE GOLD STANDARD OF PURE, CONSISTANT, PROVEN PROTIEN!! There is NOTHING better and more complete than whole egg protien. I am sure everyone on this board will agree with that.

Eggs are a great source of protein...but most of the companies no longer have 100% egg due to bird flu three years or so back.

Whey with egg is phenonemal...Beverly used to have MP with 100% Egg as a shake...