Soy protein?

[Parm]

Hey guys, I'm just about to start my diet and was wandering if soy protein is o.k. I read somewhere that soy lowers testosterone and can cause gyno/estrogen. However as a vegetarian I get my protein from mainly whey shakes and soy. Would this be a problem?

Btw I take in around 300g of protein a day, 100g comes from soy, the rest from shakes and nuts.

Thanks in advance!

 

[Y_lifter]

You can google "SOY bodybuilding" and find about a 50-50 mix of articles
and research with both Soy Sucks and Soy is Awesome from my experience.
Both sides may have valid test results or both may be skewed.

Read and use your own judgement.

Being a Vegie, you may have little choice, especially if you are a Vegan.
Most Everyone agrees that Whey is awesome.
Try Milk or Egg maybe if you feel Soy isn't good and you can eat that.

 

[Cynical Simian]

macro (of Anafit and formerly the EF A A S forum) posted this on another board earlier today (boldface added by me):

1: 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 - growth hormone (somatropin) - - growth hormone (somatropin) - - growth hormone (somatropin) - - growth hormone (somatropin) - - growth hormone (somatropin) - , 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. [email protected]

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 - leutenizing hormone - - leutenizing hormone - - leutenizing hormone - - leutenizing hormone - - leutenizing hormone - ) 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.

IMO, you definitely should find a good slow-digesting dairy protein powder (i.e., some or all casein) to use in place of soy.