ST LOUIS, July 20 /PRNewswire/ -- A new study published by the American Society for Reproductive Medicine finds that soyfoods and soy isoflavone supplements have no significant effect on male reproductive hormone levels in men. The literature review indicates that soy does not decrease testosterone levels.
Led by Jill M. Hamilton-Reeves, PhD, RD, of St. Catherine's University, St. Paul, Minnesota, researchers assessed the effects of soy protein and soy isoflavones on measurements of male reproductive hormones. Findings, just published online in Fertility and Sterility, a publication of the American Society for Reproductive Medicine, demonstrate no significant effect of soy protein or soy isoflavone intake on circulating levels of testosterone, sex hormone-binding globulin or free testosterone in men.
The comprehensive meta-analysis examined the existing scientific literature including all clinical studies examining soy's effect on male reproductive hormones published before July 1, 2008. Fifteen placebo-controlled treatment groups with baseline and ending measures were analyzed. Thirty-two reports involving 36 treatment groups were also assessed in simpler statistical models. Studies published after July 1, 2008, which were not included in the meta-analysis, support the conclusions of the meta-analysis.
Reproductive endocrinologist William R. Phipps, MD, of the University of Rochester Medical Center, a co-author of the analysis stated, "As a high-quality source of protein that is relatively low in saturated fat, soy can be an important part of a heart-healthy diet and may contribute to a decreased risk of coronary heart disease." He noted that some men have been reluctant to consume soyfoods due to concerns about estrogen-like effects of soy isoflavones, often referred to as phytoestrogens. But according to Phipps, "it is important for t
|SOURCE United Soybean Board|
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