Can the use of probiotics in association with isoflavone improve the symptoms of genitourinary syndrome of menopause? Results from a randomized controlled trial

OBJECTIVE: To evaluate the effect of isoflavone administration, either in conjunction with probiotic use or not, on the symptoms of genitourinary syndrome of menopause, and compare the effects with those of hormone therapy. METHODS: A randomized clinical trial was conducted on 60 postmenopausal women aged 40 to 60 years, randomly assigned to receive oral isoflavone (150 mg dry extract of glycine max) alone or isoflavone plus probiotic (Lactobacillus acidophilus, Lactobacillus casei, Lactococcus lactis, Bifidobacterium bifidum, and Bifidobacterium lactis) or hormone therapy (1 mg estradiol and 0.5 mg norethisterone acetate). The urogenital symptom subscale of the Menopause Rating Scale and International Consultation on Incontinence Questionnaire-Short Form were used to assess genitourinary symptoms. Vaginal maturation value, pH, vaginal health score, and vaginal flora were used to evaluate vaginal atrophy. Equol, equol intermediate, O-dimethylangolensin, and aglycones were measured using gas chromatography coupled to mass spectrometry. RESULTS: After 16 weeks of treatment, the urogenital symptoms, mainly vaginal dryness and sexual problem complaints, improved significantly in the hormone therapy group. There was a significant increase in the daidzein, glycitein, equol intermediate, and O-dimethylangolensin contents after 16 weeks in the isoflavone plus probiotic group. The maturation value, vaginal pH, and vaginal flora improved in the hormone therapy group. The vaginal health score increased in the isoflavone and hormone therapy groups. CONCLUSIONS: Probiotics improved the metabolism of isoflavones after 16 weeks of treatment. However, the increase in the contents of isoflavones and their metabolites failed to yield an estrogenic effect on the urogenital tract and relieve the vulvovaginal symptoms.