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Benefits of Soy Isoflavone Therapeutic Regimen on Menopausal Symptoms

Han, Kyung K. MD; Soares, Jose M. Jr MD; Haidar, Mauro A. MD, PhD; de Lima, Geraldo Rodrigues MD, PhD; Baracat, Edmund C. MD, PhD

Original Research

OBJECTIVE To examine the change in menopausal symptoms and cardiovascular risk factors in response to 4 months of daily 100-mg soy isoflavone in postmenopausal women.

METHODS In this double-blind, placebo-controlled study, 80 women were randomly assigned to isoflavone (n = 40) and placebo (n = 40) treatment. The menopausal Kupperman index was used to assess change in menopausal symptoms at baseline and after 4 months of treatment. Cardiovascular risk factors were assessed by evaluating plasma lipid levels, body mass index, blood pressure, and glucose levels in the participants. To examine the effects of this regime on endogenous hormone levels, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and 17β-estradiol were measured. Transvaginal sonography was performed to quantify endometrial thickness.

RESULTS The data showed a decrease in menopausal symptoms (P < .01, paired t test, two-tailed, between baseline and isoflavone groups, and P < .01, unpaired t test, between placebo and isoflavone groups). Total cholesterol and low-density lipoprotein decreased significantly in the isoflavone group compared with the baseline or placebo group (P < .001, paired t test, two-tailed, between baseline and isoflavone groups, and P < .01, unpaired t test, between placebo and isoflavone groups). The isoflavone treatment appeared to have no effect on blood pressure, plasma glucose, and high-density lipoprotein and triglyceride levels.

CONCLUSION This study suggests that isoflavone 100-mg regime treatment may be a safe and effective alternative therapy for menopausal symptoms and may offer a benefit to the cardiovascular system.

Soy isoflavone treatment decreases menopausal symptoms and low-density lipoprotein cholesterol levels.

Department of Gynecology, Escola Paulista de Medicina/Federal University of Sao Paulo, Sao Paulo, Brazil.

Address reprint requests to: Edmund C. Baracat, MD, PhD, Federal University of Sao Paulo, Department of Gynecology, Rua Dr. Diogo de Faria, 1087 cj. 610 v. Clementino, Sao Paulo SP 04037–003, Brazil; E-mail:

We would like to thank Dr. Mercedes C. Panizzi; Marcos G. Mandarino and Dr. Akio Kikuchi (Brazilian Research Institute of Agriculture [EMBRAPA], Brasilia, Brazil); Dr. Tai W. Kwon and Dr. Sung R. Kim (Korea Food Research Institute, Seoul, Korea); Dr. Dong K. Yim (Food Technology of Campinas-[ITAL]), Campinas, Brazil; and Dr. Myoung K. Park (Life Science Research Center of Eugenbio Inc., Seoul, Korea) for their priceless efforts and cooperation in our study.

Received July 11, 2001. Received in revised form November 1, 2001. Accepted November 9, 2001.

© 2002 The American College of Obstetricians and Gynecologists