Comment Re:What they don't tell you (Score 1) 588
Only one study has examined soy and whey protein supplementation together in conjunction with resistance training. Kalman et al. [46] reported that after 12 weeks of supplementation with soy there were no significant differences between groups for total testosterone, free testosterone, and SHBG. This study expanded upon the limited prior research examining the effects of soy and whey protein supplementation on testosterone, SHBG, and cortisol responses to an acute bout of resistance exercise. Contrary to popular misconceptions, soy protein supplementation does not appear to hinder anabolic signaling postexercise by means of eliciting increases in estradiol concentrations. However, our main findings demonstrate that 14 days of supplementation with soy protein does appear to blunt serum testosterone. In addition, whey might influence the response of cortisol during an acute bout of resistance exercise by also blunting its normal increase. Further research will need to explore a possible interaction effect on sex hormone binding globulin.