Soy intake related to menopausal symptoms, serum lipids, and bone mineral density in postmenopausal Japanese women

Author: Somekawa Y, Chiguchi M, Ishibashi T, Aso T
Publication: Obstet Gynecol. 2001 Jan;97(1):109-15

During menopause, women suffer from low body estrogen levels, which caused increased risk of osteoporosis and heart diseases. Soy isoflavones are the most consumed phytoestrogens. Asian people who consume 10 to 100 times more isoflavones than Western people have less risk of osteoporosis. The objective of this study was to investigate the influence of soy isoflavones on menopausal symptoms, bone mineral density and lipid profiles of Japanese menopausal woman.

In total 478 postmenopausal were involved in the study. After selection, they were divided in four groups depending on quantity of daily isoflavones consumption. Question were asked to determine soy intake at the present age and at the age of 40 years. Each of these groups was subdivided in two subgroups: women in early menopause and women in late menopause. The women reported typical menopause symptoms at the time of enrolment such as hot flushes, sweating, chills, sleep problems, irritability, depression, headaches, palpitations, backache or arching joins.

The average (mean) daily intake of soy isoflavones was 54.3 mg. The main soy products were soybean curd, fermented soybeans, soybean paste, boiled soybeans, soy milk, soy flour and soy sauce. The main source of soy isoflavones was soybean curd followed by fermented soybeans. The weight and menopausal status had no influence on bone mineral density. Women with the highest intake of soy isoflavones showed a significant higher bone mineral density compared to women with lower soy isoflavones intake. The menopausal symptoms palpitation, backaches and aching joints were significantly less severe in the group with the highest isoflavones intake. Other menopausal symptoms were less severe in the high isoflavones group but the differences were not significant.

The study concluded that high consumption of soy isoflavones is associated with increased bone mass density in postmenopausal women. Consumption of soy isoflavones might be useful to prevent symptoms related with low estrogen levels.