ABSTRACT
Several interesting events have taken place since the publication of the original chapter on phytoestrogen (Oomah, 2002). Most important of all was the early termination of one of the trial arms of the Women’s Health Initiative (WHI) that was evaluating hormone replacement therapy (HRT) (Writing Group for the Women’s Health Initiative Investigators, 2002), although information has been updated recently (Stefanick et al., 2006). This led to uncertainty in the risks and benefits of nonhormonal therapies including diets high in phytoestrogens for alleviating hot flashes after menopause and their avoidance as far as possible. Dietary exposure of phytoestrogens thus became a priority in human health resulting in the establishment and compilation of a comprehensive database for lignan contents of Dutch plant foods (Milder et al., 2005), for isoflavones in diets in the United Kingdom (Clarke and Lloyd, 2004) followed by further emphasis and focus on exposure and toxicology of phytoestrogens regarding human health (NTP-CERHR Expert Panel Report on the reproductive and developmental toxicity of genistein, 2006). In this regard, the United Kingdom Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) has advanced a definition of phytoestrogen as ‘‘any plant substance or metabolite that induces biological responses in vertebrates and can mimic or modulate the actions of endogenous estrogens usually by binding to estrogen receptors.’’
