No abstract

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.

Postmenopausal women using tibolone characterized as equol producers had lower blood pressure compared to non-equol producers. Soy supplementation for 2 months had no blood pressure-lowering effect.

In conclusion, isoflavone treatment did not affect serum cholesterol efflux potential in postmenopausal women. Based on our findings, isolated isoflavones do not provide vascular benefits by improving cholesterol efflux.

Objectives-To determine whether co-administration of soy during tibolone treatment would prevent tibolone-induced dyslipoproteinemia in postmenopausal monkeys and women.Methods-Surgically postmenopausal cynomolgus monkeys (n=18) were assigned randomly to one of four dietary regimens in a Latin Square crossover design, such that all animals received all diets for 14 weeks with a 4-week washout period: 1) Casein/lactalbumin (CL); 2) Tibolone (Tib, 1.25mg/day women's equivalent); 3) Soy (138mg isoflavones/day women's equivalent); 4) Soy+Tib. Postmenopausal women on tibolone treatment were randomized to receive soy powder (52 g of soy protein containing 112 mg isoflavones) or placebo (containing 52 g of milk protein) daily in a crossover trial for 8 weeks with a 4-week washout period.Results-Monkeys given Tib alone had ~14% increase in plasma LDL+VLDL-C; whereas those given soy combined with tibolone had significant (~22%) reductions. Tib treated monkeys had reductions in plasma HDL-C of about 48% vs. no reductions in Soy+Tib. In postmenopausal women using tibolone, soy reduced plasma LDL-C concentrations by ~10% from baseline without a change in HDL-C.Conclusions-Co-administration of soy during tibolone treatment improved the lipoprotein profile in both monkeys and women; however, the effects were more robust in monkeys.