Impact of soy supplementation on sex steroids and vascular inflammation markers in postmenopausal women using tibolone: role of equol production capability.
OBJECTIVE
Tibolone is often taken concurrently with soy. Tibolone, soy and equol-producing capacity each affect vascular health, whereas their concomitant effects are unknown. We studied the effects of soy on sex steroids and vascular inflammation markers in long-term tibolone users.


METHODS
Postmenopausal women (n = 110) on tibolone were screened with a soy challenge to find 20 equol producers and 20 non-producers. All women were treated for 8 weeks in a cross-over trial with soy (52 g of soy protein containing 112 mg of isoflavones) or placebo. Serum estrone, 17beta-estradiol, testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), C-reactive protein (CRP), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet-selectin (P-selectin) were assessed.


RESULTS
Soy decreased (7.1%) the estrone level, significantly (12.5%) only in equol producers (from 80.2 +/- 10.8 to 70.3 +/- 7.0 pmol/l; p = 0.04). Testosterone was reduced (15.5%; from 586 +/- 62.6 to 495 +/- 50.1 pmol/l, p = 0.02) during soy treatment, and more markedly in equol producers than non-producers (22.1% vs. 10.0%). No changes appeared in SHBG, CRP or ICAM-1, but VCAM-1 increased (9.2%) and P-selectin decreased (10.3%) during soy treatment.


CONCLUSIONS
Soy modified the concentrations of estrone, testosterone and some endothelial markers. Equol production enforced these effects. Soy supplementation may be clinically significant in tibolone users.
Törmälä
R
R
Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Finland.
Appt
S
S
Clarkson
T B
TB
Mueck
A O
AO
Seeger
H
H
Mikkola
T S
TS
Ylikorkala
O
O
D002097:C-Reactive Protein / Q000032:analysis; D018592:Cross-Over Studies; D060754:Equol; D020847:Estrogen Receptor Modulators / Q000627:therapeutic use*; D004970:Estrone / Q000097:blood; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D007529:Isoflavones / Q000378:metabolism*; D008875:Middle Aged; D009652:Norpregnenes / Q000627:therapeutic use*; D019007:P-Selectin / Q000097:blood; D017698:Postmenopause; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D030262:Soybean Proteins / Q000008:administration & dosage*; D013739:Testosterone / Q000097:blood; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D020847:Estrogen Receptor Modulators; D007529:Isoflavones; D009652:Norpregnenes; D019007:P-Selectin; D012738:Sex Hormone-Binding Globulin; D030262:Soybean Proteins; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D004970:Estrone; D013739:Testosterone; D060754:Equol; D002097:C-Reactive Protein; C027385:tibolone