Effects of soy isoflavones on menopausal neurovegetative symptoms

Dietary soy supplementation may reduce the incidence of hot flushes in postmenopausal women due to the presence of phytoestrogens in soy foods. The aim of this study was to assess the effects of a 3-month administration of different doses of either oral or transdermal soy isoflavones on climacteric complaints in postmenopausal women.

Sixty postmenopausal women were assigned randomly to one of the following groups: groups A and B received 50 mg/day or 75 mg/day of oral isoflavones respectively, while groups C and D received 6 mg/day or 12 mg/day of transdermal isoflavones. A control group (group E) was composed of 15 patients that did not receive any treatment. Hot flushes, Kupper-man index and vaginal dryness at baseline and then after 5, 9 and 13 weeks were evaluated.

The isoflavone treatment led to a progressive significant (p<0.01) reduction of the number of hot flushes in the groups A, B and D with a dose-related effect in group D. At week 13, the Kupperman index and hot flush score decreased significantly in all the treated groups, while vaginal dryness score was reduced only in group B.

Our findings suggest that both oral and transdermal soy isoflavones are effective to attenuate slight to moderate menopausal neurovegetative symptoms with a dose-related effect.