Isoflavones May Reduce Insomnia Symptoms in Postmenopausal Women

Laurie Barclay, MD

February 09, 2011

February 9, 2011 — Isoflavones may reduce insomnia symptoms as well as hot flashes in postmenopausal women, according to the results of a controlled, double-blinded study reported in the February issue of Menopause.

"Most postmenopausal women have insomnia," write Helena Hachul, MD, PhD, from the Departamento de Psicobiologia and Ginecologia, Universidade Federal de São Paulo in Brazil, and colleagues. " Recent reports have documented that the phytohormones, isoflavones, are capable of reducing the symptoms of climacterium."

The study goal was to evaluate subjective and objective sleep parameters in postmenopausal women with insomnia and to measure changes in these parameters during treatment with isoflavones.

In this study of 38 postmenopausal women with insomnia, 1 group received 80 mg isoflavones daily for 4 months, and a second group received a placebo daily for the same period. Questionnaires and polysomnography allowed qualitative and quantitative analysis of sleep. Between-group comparisons were performed using Student's t-test and analysis of variance, and Pearson's correlation coefficient was used to test correlations.

For the isoflavone group vs the placebo group, sleep efficiency measured by polysomnography increased significantly (from 77.9% to 83.9% vs from 77.6% to 81.2%). In addition, frequency of insomnia was reduced more readily in the isoflavone group. At the beginning of the study, 94.7% of women in the placebo group had moderate or intense insomnia compared with 63.2% at the end of the study; whereas in the isoflavone group these percentages were 89.5% and 36.9%, respectively.

Isoflavones were also effective in reducing the number of hot flashes in postmenopausal women with insomnia compared with the placebo group (P = .001). This trend became apparent after 2 months of treatment, but the results became significant only after the fourth month of treatment. The intensity of hot flashes was significantly lower in the isoflavone group than in the placebo group at both evaluation points (months 2 and 4 of treatment; 1.6 vs 5.8 and 0.5 vs 3.8; P < .001).

"In postmenopausal women with insomnia, isoflavone treatment was effective in reducing insomnia symptoms, which was confirmed by increased sleep efficiency as observed by polysomnographic analysis," the study authors write.

Limitations of this study include its small sample size.

"Because sleep complaints are common during menopause," the study authors recommend that "future studies...include other sources of alternative and/or complementary treatment for insomnia in postmenopausal women."

Associação Fundo de Incentivo à Psicofarmacologia, Fundação de Amparo à Pesquisa do Estado de São Paulo, Fundação de Amparo à Pesquisa do Estado de São Paulo/Centros de Pesquisa, Inovacao e Difusao, and Conselho Nacional de Desenvolvimento Científico e Tecnol&oactue;gico supported this study. The drug was supplied by Zambon Group (both placebo and active ingredient [Fisiogen]). Three of the study authors received fellowships from Conselho Nacional de Desenvolvimento Científico e Tecnológico. The study authors have disclosed no relevant financial relationships.

Menopause. 2011;18:178-184. Abstract


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