Phytoestrogen content of foods--a compendium of literature values.

Plant compounds with estrogenic activity may play a role in cancer prevention, moderation of menopausal symptoms, and other health effects. To facilitate research on these possible actions, the literature was reviewed for quantitative data on the levels of known phytoestrogens (daidzein, genistein, coumestrol, formononetin, and biochanin A) in food plants. For comparative purposes, all phytoestrogen levels were recalculated on a wet weight basis. Details on analytic procedures are given as well. High-performance liquid chromatography was the method most often used to analyze these compounds in foods. Most significant sources of isoflavone and coumestan phytoestrogens include soybeans, soy flour, soy flakes, isolated soy protein, traditional soy foods such as tofu and soy drinks, second-generation say foods, sprouts, and other legumes. Finally, medians among reported values of phytoestrogen content are provided for some of the most commonly eaten foods with quantitative data available. These may be used to calculate dietary intake of daidzein, genistein, coumestrol, formononetin, and biochanin A.