Postmenopausal women and dietary phytoestrogen intake considered low.




Journal of Nutrition

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Phytoestrogens are plant chemicals that have the ability to create estrogenic effects by binding to estrogen receptors. During the past decade, a fair amount of attention has been paid to the phytoestrogens in products made from soy. There are positive health benefits associated with the intake of phytoestrogens ranging from cardiovascular benefits to benefits associated with relieving the symptoms of menopause. While the benefits of phytoestrogens are just beginning to be studied, no one to date has identified what amount of phytoestrogens is in the average Western diet.
This study was designed to estimate the intake of isoflavones, coumestans, and lignans in the diets of healthy Western postmenopausal women. Food sources of phytoestrogens and the concentrations of them within food sources were determined. The subjects of this study were 964 postmenopausal, Caucasian women who participated in the Framingham Offspring Study and completed the Willett food-frequency questionnaire (FFQ). With the isoflavones daidzein, genistein, formononetin, and of biochanin A being evaluated individually, the median total intake of isoflavones was measured.
The authors of the study indicated that previously all studies on hormone-related diseases focused on Asian populations whose intake of phytoestrogens comes from a soy rich diet, or from trials with Western populations who are given soy supplements. The average intake of phytoestrogens from food sources in Western cultures compared to those in Asian cultures is low. The authors noted, “The effects of daily intakes of low dietary phytoestrogens have not yet been studied. To be able to study dietary phytoestrogen intake more precisely in relation to disease risk and incidence, a comprehensive and complete database of isoflavonoid, coumestan and lignan contents of the most common foods in the Western diet should be developed, including data on milk products and fast-food (possibly containing soymilk or soy flour), to increase the comprehensiveness and accuracy of the nutrient database.” Based on intake of foods known to have phytoestrogens and reported in this study, Western women’s intake is equal to or less than 1mg per day, whereas in Asian cultures, the daily intake is approximately 20 to 80 mg.1


1. de Kleijn MJJ, van der Schouw YT, Wilson PWF, Adlercreutz H. Intake of Dietary Phytoestrogens Is Low in Postmenopausal Women in the United States: The Framingham Study. Journal of Nutrition. Jun 2001;131:1826-1832.