ABSTRACT
In general, compounds classified as “endocrine disruptors” are regarded as adverse substances and presumed to have deleterious effects on mammalian systems. Human exposure to these compounds is thus recommended to be as limited as possible and great effort is being undertaken to reduce or eliminate these compounds in the environment. Phytoestrogens occur at high levels in variety of foods, particularly those that are soy-based, such as soy infant formula, tofu, and soy flour. Numerous dietary supplements are also available that contain a wide range of phytoestrogens, particularly the isoflavones. Lignans are a minor component of plant cell walls. The plant lignans matairesinol and secoisolariciresinol are converted to the mammalian lignans enterlactone and enterodiol, respectively, by the resident bacterial flora of the gut. The isoflavonoids are divided into three major classes: isoflavones, isoflavans, and coumestans, of which the isoflavones are the most widely studied group. Phytoestrogenic isoflavonoids are less prevalent than lignans.
