TY - JOUR
T1 - Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men
T2 - Results of a meta-analysis
AU - Hamilton-Reeves, Jill M.
AU - Vazquez, Gabriela
AU - Duval, Sue
AU - Phipps, Bill
AU - Kurzer, Mindy S
AU - Messina, Mark J.
PY - 2010/8
Y1 - 2010/8
N2 - Objective: To determine whether isoflavones exert estrogen-like effects in men by lowering bioavailable T through evaluation of the effects of soy protein or isoflavone intake on T, sex hormone-binding globulin (SHBG), free T, and free androgen index (FAI) in men. Design: PubMed and CAB Abstracts databases were searched through July 1, 2008, with use of controlled vocabulary specific to the databases, such as soy, isoflavones, genistein, phytoestrogens, red clover, androgen, testosterone, and SHBG. Peer-reviewed studies published in English were selected if [1] adult men consumed soy foods, isolated soy protein, or isoflavone extracts (from soy or red clover) and [2] circulating T, SHBG, free T, or calculated FAI was assessed. Data were extracted by two independent reviewers. Isoflavone exposure was abstracted directly from studies. Main Outcome Measure(s): Fifteen placebo-controlled treatment groups with baseline and ending measures were analyzed. In addition, 32 reports involving 36 treatment groups were assessed in simpler models to ascertain the results. Result(s): No significant effects of soy protein or isoflavone intake on T, SHBG, free T, or FAI were detected regardless of statistical model. Conclusion(s): The results of this meta-analysis suggest that neither soy foods nor isoflavone supplements alter measures of bioavailable T concentrations in men.
AB - Objective: To determine whether isoflavones exert estrogen-like effects in men by lowering bioavailable T through evaluation of the effects of soy protein or isoflavone intake on T, sex hormone-binding globulin (SHBG), free T, and free androgen index (FAI) in men. Design: PubMed and CAB Abstracts databases were searched through July 1, 2008, with use of controlled vocabulary specific to the databases, such as soy, isoflavones, genistein, phytoestrogens, red clover, androgen, testosterone, and SHBG. Peer-reviewed studies published in English were selected if [1] adult men consumed soy foods, isolated soy protein, or isoflavone extracts (from soy or red clover) and [2] circulating T, SHBG, free T, or calculated FAI was assessed. Data were extracted by two independent reviewers. Isoflavone exposure was abstracted directly from studies. Main Outcome Measure(s): Fifteen placebo-controlled treatment groups with baseline and ending measures were analyzed. In addition, 32 reports involving 36 treatment groups were assessed in simpler models to ascertain the results. Result(s): No significant effects of soy protein or isoflavone intake on T, SHBG, free T, or FAI were detected regardless of statistical model. Conclusion(s): The results of this meta-analysis suggest that neither soy foods nor isoflavone supplements alter measures of bioavailable T concentrations in men.
KW - SHBG
KW - Soy
KW - isoflavones
KW - phytoestrogens
KW - red clover
KW - testosterone
UR - http://www.scopus.com/inward/record.url?scp=77955588510&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955588510&partnerID=8YFLogxK
U2 - 10.1016/j.fertnstert.2009.04.038
DO - 10.1016/j.fertnstert.2009.04.038
M3 - Article
C2 - 19524224
AN - SCOPUS:77955588510
SN - 0015-0282
VL - 94
SP - 997
EP - 1007
JO - Fertility and Sterility
JF - Fertility and Sterility
IS - 3
ER -