Psychological assessment of the effects of treatment with phytoestrogens on postmenopausal women: a randomized, double-blind, crossover, placebo-controlled study.

Objective: To investigate the effects of soy isoflavones on mood and cognitive function in postmenopausal women.

Design: Randomized, double-blind, cross-over, placebo-controlled trial.

Setting: University Hospital, Milan, Italy; A.G.UN.CO. Obstetrics and Gynaecology Centre, Rome, Italy.

Patient(s): Seventy-eight postmenopausal women.

Intervention(s): We administered 60 mg/day isoflavones or placebo for 6 months. After a washout period of 1 month, the patients who had been treated with phytoestrogens received placebo, and those who previously received placebo were administered phytoestrogens (for 6 months).

Main Outcome Measure(s): Cognitive performance and mood were assessed by a battery of tests at the end of each treatment period. At the end of the study, the patients were also asked whether they preferred the first or second treatment.

Result(s): The 17 scores on cognitive performance test and the 6 for mood assessments 6 showed an advantage for the treatment with phytoestrogens. Similarly, of the 8 visual analogue scales used to indicate mood, 7 improved significantly after the treatment with phytoestrogens. Moreover, 49 patients preferred phytoestrogens, 9 placebo, and 18 had no preference. The preference was not related to the order of treatment.

Conclusion(s): These results suggest that isoflavones may have positive effects on postmenopausal women improving cognitive performance and mood.