Objectives:

Equol, a metabolite of the isoflavone daidzein, is hypothesized to play a major role in the health benefits of soy. We examined the effect of a new S-equol supplement on menopausal symptoms and mood states.

Design:

We conducted a randomized, double-blind, placebo-controlled trial with our new equol supplement for 12 weeks with 134 Japanese women (aged 40-59 years). They were randomly assigned to three groups: placebo (n= 44), 10 mg of equol per day (EQ-1; n= 44), and 10 mg of equol three times per day (EQ-3; n= 46). Habitual isoflavone intake was limited to 20 mg/d. Participants completed menopausal symptom and Profile of Mood States questionnaires at baseline and postintervention. Physical examination and blood and 24-hour urine collection were performed at baseline and postintervention.

Results:

At baseline, total menopausal symptom score varied by menopausal and equol producer status (34.3% producers). A total of 127 participants (94.8%) completed the trial. No adverse effects were reported, except for a systemic rash in one EQ-3 woman. The anxiety scores of equol producers were lower than those of nonproducers (P< 0.05). Significant differences between premenopausal and perimenopausal/postmenopausal symptom scores were observed for anxiety, somatic, and total scores. After the EQ-3 intervention, perimenopausal/postmenopausal equol nonproducers showed significant decreases from baseline in all menopausal symptom scores except depression (P< 0.01). Compared with placebo, the EQ-3 group showed significant decreases in depression scores (P< 0.05), as well as significant decreases in Tension-Anxiety (P< 0.05), Depression-Dejection (P< 0.05) and Fatigue (P< 0.01) and increases in Vigor (P< 0.05) of the Profile of Mood States.

Conclusion:

S-equol supplement improved mood-related symptoms in perimenopausal/postmenopausal equol nonproducers.

Epidemiological studies suggest that high consumption of soy isoflavones may account for the lower frequency of menopausal symptoms in Asian populations. 1 Recent studies found a 2-week hot flash prevalence of 22.1% among Japanese women compared with 36.6% and 46.5% for white American and African American women, respectively. 2-4 Adlercreutz et al 5 suggested that the estrogen-like properties of isoflavones might account for the low prevalence of hot flashes experienced by Japanese women.