Dietary soy containing phytoestrogens does not have detectable estrogenic effects on hepatic protein synthesis in postmenopausal XXXX .

@entity172 @entity1 @entity3093 @entity9027 @entity6400
BACKGROUND: Dietary phytoestrogens are ligands for the @entity172 receptor and may mimic estrogenic effects in vivo. OBJECTIVE: To assess the biological activity of @entity3093 phytoestrogens, we analyzed the effect of dietary soy @entity3093 supplementation on in vivo bioassays of estrogenicity. DESIGN: Fifty healthy postmenopausal @entity1 aged 50-75 y participated in a double-blind, placebo-controlled trial in which they received either soy protein isolate (40 g soy protein, 118 mg @entity6400 ) or casein placebo. Measurements were made at baseline and at 3 mo. Urinary @entity3093 excretion was measured to reflect compliance. The bioassays of estrogenicity included measurement of hepatic proteins and gonadotropin concentrations. RESULTS: Baseline characteristics were not significantly different between the soy and placebo groups. Urinary @entity3093 excretion increased in the soy group and at the end of 3 mo was higher in the soy group than in the placebo group. In plasma samples from both groups, C-reactive protein increased significantly over the 3-mo treatment period, whereas sex hormone-binding globulin and thyroid-binding globulin decreased significantly. However, there were no significant differences between the groups in hepatic protein synthesis (change over 3 mo +/- SEM in the soy and placebo groups, respectively): C-reactive protein, 0.42 +/- 0.2 and 0.48 +/- 0.2 U/mL; sex hormone-binding globulin, -6.9 +/- 1.5 and -10.0 +/- 2.1 micro g/mL; thyroid-binding globulin, -16 +/- 8 and -26 +/- 7 nmol/L. Furthermore, gonadotropin and @entity9027 concentrations did not change significantly in either group. CONCLUSIONS: In healthy postmenopausal @entity1 , dietary soy @entity6400 do not affect in vivo biological indicators of estrogenicity, including hepatic protein synthesis and gonadotropin concentrations. This suggests that soy @entity6400 have little biologically relevant estrogenic effect in vivo in postmenopausal @entity1 .
