Plant phytoestrogenOver the past 30 years the health effects of soy foods have been rigorously investigated. Approximately 2,000 soy-related peer-reviewed papers are published annually. Much of this research can be attributed to soy foods being uniquely rich sources of isoflavones. This point is illustrated by the mean daily isoflavone intake of 30 to 50 mg among older individuals in Japan1,2 whereas in the United States3 and Europe,4 per capita intake is less than 3 mg. Isoflavones have been purported to exert several health benefits, from reducing cancer risk5,6 to alleviating menopausal symptoms7 and improving memory. 8 On the other hand, some concerns about possible adverse effects of isoflavones have arisen, although a recently published comprehensive technical review concluded that neither soy foods nor isoflavones exert endocrine-disrupting effects.9The three isoflavones in soybeans—genistein (molecular weight, 270 g/mol), daidzein (molecular weight, 254.2 g/mol) and glycitein (...
