Food sources of the various phytoestrogens are shown in the next few slides. The main source of isoflavones are soybeans, but also in various dried beans, and more importantly in processed foods because of the addition of soy products, such as flour or soy protein. The impact of hidden sources of isoflavones was illustrated in a report that showed, among men who did not consume soy, urinary isoflavone excretion was positively correlated with intake of high-fat and processed meats. These hidden sources of a putatively beneficial phytochemical may be obscured by otherwise unhealthy food choices. Furthermore, our ability to measure exposure to phytoestrogens will become more difficult as more processed foods have soy added without a consequent updating of our food composition data.