The effects of soy and whey protein supplementation on acute hormonal responses

Nelson Vergel

Founder, ExcelMale.com
For many resistance-trained men concerns exist regarding the production of estrogen with the consumption of soy protein when training for muscle strength and size. Thus, the purpose of this investigation was to examine the effects of soy and whey protein supplementation on sex hormones following an acute bout of heavy resistance exercise in resistance trained men.

J Am Coll Nutr. 2013;32(1):66-74. doi: 10.1080/07315724.2013.770648.
The effects of soy and whey protein supplementation on acute hormonal reponses to resistance exercise in men.Kraemer WJ, Solomon-Hill G, Volk BM, Kupchak BR, Looney DP, Dunn-Lewis C, Comstock BA, Szivak TK, Hooper DR, Flanagan SD, Maresh CM, Volek JS.
[h=3]Source[/b]Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA. [email protected]

[h=3]Abstract[/b][h=4]OBJECTIVE:[/b]

[h=4]METHODS:[/b]Ten resistance-trained men (age 21.7 ± 2.8 [SD] years; height 175.0 ± 5.4 cm; weight 84.2 ± 9.1 kg) volunteered to participate in an investigation. Utilizing a within subject randomized crossover balanced placebo design, all subjects completed 3 experimental treatment conditions supplementing with whey protein isolate (WPI), soy protein isolate (SPI), and maltodextrin placebo control for 14 days with participants ingesting 20 g of their assigned supplement each morning at approximately the same time each day. Following supplementation, subjects performed an acute heavy resistance exercise test consisting of 6 sets of 10 repetitions in the squat exercise at 80% of the subject's one repetition maximum.
[h=4]RESULTS:[/b]This investigation observed lower testosterone responses following supplementation with soy protein in addition to a positive blunted cortisol response with the use of whey protein at some recovery time points. Although sex hormone binding globulin (SHBG) was proposed as a possible mechanism for understanding changes in androgen content, SHBG did not differ between experimental treatments. Importantly, there were no significant differences between groups in changes in estradiol concentrations.
[h=4]CONCLUSION:[/b]Our main findings demonstrate that 14 days of supplementation with soy protein does appear to partially blunt serum testosterone. In addition, whey influences the response of cortisol following an acute bout of resistance exercise by blunting its increase during recovery. Protein supplementation alters the physiological responses to a commonly used exercise modality with some differences due to the type of protein utilized.




More info on soy and why to avoid it: http://fitlife.tv/10-reasons-to-avoid-soy-at-all-costs/
 

Nelson Vergel

Founder, ExcelMale.com
Soy Tanks Testosterone

Perhaps the most startling study came out of the University of North Carolina at Chapel Hill a few years back.24 Completed for the National Cancer Institute, it found soy-eating men experienced “nipple discharge, breast enlargement, slight decreases in testosterone and hot flashes.” In an attempt to downplay these rather sensational findings, lead researcher Steven H. Zeisel MD, reported nothing “serious” was found, even though they administered doses up to thirty times what might get from “normal foods.” To reassure men, he stated, “I don't think there are a lot of estrogenic worries. Your testicles will not shrink and you won't have massive breast enlargement.” 25
 

Online statistics

Members online
3
Guests online
5
Total visitors
8

Latest posts

Top