Consumption of a soy drink has no effect on cognitive function but may alleviate vasomotor symptoms in post-menopausal women; a randomised trial.

PURPOSE: Cognitive decline is commonly reported during the menopausal transition, with memory and attention being particularly affected. The aim of this study was to investigate the effects of a commercially available soy drink on cognitive function and menopausal symptoms in post-menopausal women. METHODS: 101 post-menopausal women, aged 44-63 years, were randomly assigned to consume a volume of soy drink providing a low (10 mg/day; control group), medium (35 mg/day), or high (60 mg/day) dose of isoflavones for 12 weeks. Cognitive function (spatial working memory, spatial span, pattern recognition memory, 5-choice reaction time, and match to sample visual search) was assessed using CANTAB pre- and post-the 12 week intervention. Menopausal symptoms were assessed using Greene's Climacteric Scale. RESULTS: No significant differences were observed between the groups for any of the cognitive function outcomes measured. Soy drink consumption had no effect on menopausal symptoms overall; however, when women were stratified according to the severity of vasomotor symptoms (VMS) at baseline, women with more severe symptoms at baseline in the medium group had a significant reduction (P = 0.001) in VMS post-intervention (mean change from baseline score: - 2.15 ± 1.73) in comparison to those with less severe VMS (mean change from baseline score: 0.06 ± 1.21). CONCLUSIONS: Soy drink consumption had no effect on cognitive function in post-menopausal women. Consumption of ~ 350 ml/day (35 mg IFs) for 12 weeks significantly reduced VMS in those with more severe symptoms at baseline. This finding is clinically relevant as soy drinks may provide an alternative, natural, treatment for alleviating VMS, highly prevalent among western women.

The effect of a randomized 12-week soy drink intervention on everyday mood in postmenopausal women.

OBJECTIVE: Dietary soy may improve menopausal symptoms, and subsequently mediate mood. This novel study examines various doses of dietary soy drink on everyday mood stability and variability in postmenopausal women. METHODS: Community-dwelling women (n = 101), within 7 years postmenopause, consumed daily either a low (10 mg, n = 35), medium (35 mg, n = 37), or high (60 mg, n = 29) dose of isoflavones, for 12 weeks. Menopausal symptoms and repeated measures of everyday mood (positive [PA] and negative [NA] affect) (assessed at four time points per day for 4 consecutive days, using The Positive and Negative Affect Schedule) were completed at baseline and follow-up. RESULTS: The dietary soy intervention had no effect on everyday mood stability (for PA [F{2,70} = 0.95, P = 0.390] and NA [F{2,70} = 0.72, P = 0.489]) or variability (for PA [F{2,70} = 0.21, P = 0.807] and for NA [F{2,70} = 0.15, P = 0.864]), or on menopausal symptoms (for vasomotor [F{2,89} = 2.83, P = 0.064], psychological [F{2,88} = 0.63, P = 0.535], somatic [F{2,89} = 0.32, P = 0.729], and total menopausal symptoms [F{2,86} = 0.79, P = 0.458]). There were between-group differences with the medium dose reporting higher PA (low, mean 24.2, SD 6; and medium, mean 29.7, SD 6) and the low dose reporting higher NA (P = 0. 048) (low, mean 11.6, SD 2; and high, mean 10.6, SD 1) in mood scores. Psychological (baseline M = 18 and follow-up M = 16.5) and vasomotor (baseline M = 4.2 and follow-up M = 3.6) scores declined from baseline to follow-up for the overall sample. CONCLUSIONS: Soy isoflavones had no effect on mood at any of the doses tested. Future research should focus on the menopause transition from peri to postmenopause as there may be a window of vulnerability, with fluctuating hormones and increased symptoms which may affect mood.