Consumption of Lactobacillus acidophilus and Bifidobacterium longum do not alter urinary equol excretion and plasma reproductive hormones in premenopausal women

Abstract

Objective: To confirm the results of an earlier study showing premenopausal equol excretors to have hormone profiles associated with reduced breast cancer risk, and to investigate whether equol excretion status and plasma hormone concentrations can be influenced by consumption of probiotics. Design: A randomized, single-blinded, placebo-controlled, parallel-arm trial. Subjects: In all, 34 of the initially enrolled 37 subjects completed all requirements. Intervention: All subjects were followed for two full menstrual cycles and the first seven days of a third cycle. During menstrual cycle 1, plasma concentrations of estradiol (E 2 ), estrone (E 1 ), estrone-sulfate (E 1 -S), testosterone (T), androstenedione (A), dehydroepiandrosterone-sulfate (DHEA-S), and sex-hormone-binding globulin (SHBG) were measured on cycle day 2, 3, or 4, and urinary equol measured on day 7 after a 4-day soy challenge. Subjects then received either probiotic capsules (containing Lactobacillus acidophilus and Bifidobacterium longum) or placebo capsules through day 7 of menstrual cycle 3, at which time both the plasma hormone concentrations and the post-soy challenge urinary equol measurements were repeated. Results: During menstrual cycle 1, equol excretors and non-excretors were not significantly different with respect to subject characteristics, diet, or hormone concentrations. Significant inverse correlations were found between E 2 and body mass index (BMI) (P ¼ 0.02), SHBG and BMI (P ¼ 0.01), DHEA-S and dietary fiber (P ¼ 0.04), and A and protein:carbohydrate ratio (P ¼ 0.02). Probiotic consumption failed to significantly alter equol excretor status or hormone concentrations during menstrual cycle 3, although there were trends towards decreased concentrations of T (P ¼ 0.14) and SHBG (P ¼ 0.10) in the probiotic group. Conclusions: We were unable to verify a previously reported finding of premenopausal equol excretors having plasma hormone concentrations different from those of nonexcretors. Furthermore, a 2-month intervention with probiotic capsules did not significantly alter equol excretion or plasma hormone concentrations.

Daidzein-metabolizing phenotypes in relation to mammographic breast density among premenopausal women in the United States

“…The proportion of equol-and ODMA-producers in our study was similar to that reported elsewhere in predominantly Caucasian populations [16,19,35,36]. Similarly, mean percent breast density among women in this study was comparable with that reported for premenopausal women in other studies [37][38][39], although some have reported slightly higher levels of density [40,41]; this could be due to the fact that we recruited women stratified by BIRADS density score to include premenopausal women with low, as well as high, densities.…”

“…For logistical reasons, we were unable to measure breast density, hormone concentrations, and daidzein-metabolizing phenotypes on the same day. This is unlikely to have affected our findings given that the daidzein-metabolizing phenotypes are relatively stable within individuals over time [52,53] and that it does not seem possible to change the phenotypes with dietary intervention [35,[54][55][56]. Furthermore, we included only premenopausal women who were not currently using exogenous hormones and had not used them at the time of, or in the 6 months prior to, their mammogram.…”

Does equol production determine soy endocrine effects?

“…In premenopausal women, who are equol producers, the reproductive hormone pattern is consistent with lower risk of breast cancer (independent of isoflavone dose intake) [98]. However, other studies did not replicate these findings [99,100].…”

Daidzein-metabolizing phenotypes in relation to serum hormones and sex hormone binding globulin, and urinary estrogen metabolites in premenopausal women in the United States

“…However, the low soy dose provided 10 mg of isoflavones per day, which is higher than mean intakes in Western populations [39,40], and it is possible that low levels of equol may be capable of eliciting biological responses. In subsequent, relatively small, studies in pre- [30] and postmenopausal [17] women, there were no significant differences between producers and non-producers of equol and ODMA (postmenopausal women only), in circulating concentrations of estrogens or androgens in the absence of prolonged soy consumption. In our study we did not observe any statistically significant differences between producers and nonproducers of ODMA in circulating concentrations of estrogens, androgens, or SHBG.…”

“…This suggested a potential role for the equol-producer phenotype that was independent of soy or isoflavone dose. However, this was not shown in a subsequent study in premenopausal women [30]. Few studies have examined the potential health effects associated with the production of ODMA.…”