Phytoestrogen


 * Phytoestrogens** are naturally occurring in whole grains, dried beans, peas, fruits, broccoli, cauliflower, and soy; they are also as concentrated extracts from these foods. Studies have led to concerns about harmful effects synthetic estrogens must be understood alongside evidence about phytoestrogens. Although scientific evidence suggests that plant based estrogens offer nutritional benefits and are associated with healthy diets, the data is conflicting as to whether they soy-based diets have beneficial, harmful or neutral effects on breast cancer risk. Some of these grains and soy have been shown to increase tumor growth in a variety of different models. Purified soy-protein isolates are often processed to contain different concentrations of isoflavones, and their influence on mammary tumors is related to the amount of isoflavone, not the total amount of soy protein consumed. Several studies have shown that regular consumption of soy-based products or other vegetables that are high in phytoestrogens can exert a protective influence with regard to later development of breast cancer.