The effects of soy protein containing isoflavones on lipids and indices of bone resorption in postmenopausal women

Abstract

In postmenopausal women, dietary supplementation with soy protein containing isoflavones does not appear to have oestrogenic effects on markers of bone resorption. Soy protein favourably affected lipids; however, these effects (fall in triacylglycerol and no change in HDL) differ from those observed with oral oestrogen. These findings suggest that soy may not have biologically significant oestrogenic effects on bone resorption and we hypothesize that the lipid effects may be mediated, at least in part, through nonoestrogenic mechanisms.

Soy isoflavone intake inhibits bone resorption and stimulates bone formation in menopausal women: meta-analysis of randomized controlled trials

“…Twenty-two studies were excluded because of lack of indices of interest (Agnusdei et al, 1997a, b;Gambacciani et al, 1997a, b;Potter et al, 1998;Alekel et al, 2000;Wangen et al, 2000;Clifton-Bligh et al, 2001;Katase et al, 2001;Anderson et al, 2002;Chiechi et al, 2002;Lucas et al, 2002;Chen et al, 2003Chen et al, , 2004Jones et al, 2003;Schult et al, 2003;Atkinson et al, 2004;Harkness et al, 2004;Olsen et al, 2004;Mori et al, 2004a, b), non-randomization (Dalais et al, 1998), lack of a control group (Agnusdei et al, 1997a, b), insufficient original data or baseline values (Gambacciani et al, 1997a, b;Khalil et al, 2002). Thus, nine studies with a total of 432 subjects were included in this meta-analysis, in which five studies had quality score of five; three studies had quality score of four and one study had quality score of three (Morabito et al, 2002;Uesugi et al, 2002;Yamori et al, 2002;Arjmandi et al, 2003Arjmandi et al, , 2005Dalais et al, 2003;Brooks et al, 2004;Mori et al, 2004a, b;Nikander et al, 2004) (Table 1). In five of these studies, isolated soy protein that contained mainly isoflavones was used, and isoflavone tablets were used in other studies.…”

“…In the present analysis, significant reduction in urinary Dpyr did not change when studies with isoflavone intake of more than 90 mg/day were not included. Potter et al (1998) showed that 90 mg isoflavones was able to attenuate bone loss; however, Dalais et al (2003) reported that soy protein supplementation with the highest dosage of 118 mg/day isoflavones did not appear to have estrogenic effects on markers of bone resorption. This suggests that isoflavones exert biphasic dose-dependent effects on bone metabolism, stimulating osteogenesis at low concentrations and inhibiting osteogenesis at high concentrations (Dang and Lowik, 2005).…”

Phyto-oestrogens and bone health

“…It has been suggested that the differences may be a result of synergies or antagonisms among the flavones, threshold (81) Post-menopausal women 40 g ground flaxseed or wheat-based comparative control regimen daily 3 Markers of bone formation and resorption not affected by either of the treatments Arjmandi et al (82) n 71 40 g soyabean protein/d 3 Decrease in urinary DPD Dalais et al (83) Post-menopausal women, n 106 3 No effect on markers for bone resorption (urinary excretion of pyridinoline or deoxypyridinoline) Harkness et al (84) Post-menopausal women, n 19, mean age 70 . 6 (SD 6 .…”

Influencia del consumo de soja sobre la masa ósea

“…El otro trabajo con resultados negativos es el ensayo clínico de Dalais y cols. (14) en el cual se trataron a 106 mujeres postmenopáusicas divididas en dos grupos: uno con suplementación con proteínas de soja y otro placebo (sin suplementación). Los resultados fueron favorables en los niveles lipídicos (disminución de los triglicéridos, mantenimiento de los niveles de HDL) pero no se observaron efectos estrogénicos ni cambios en los marcadores de resorción ósea.…”