In normal mammogenesis, receptor sites are activated by the body s own natural increase in estrogen activity during puberty. Phytoestrogens have a balancing effect on the body. When the estrogen levels are too low, their mild estrogenic effect raises total estrogenic activity. However, when levels are higher, they compete with estrogen at cell membrane receptor sites, and create the opposite effect. She says, Phytoestrogens may stimulate growth of breast cells, but it may also stimulate abnormal breast cells.
Companies marketing phytoestrogens believe, however, that they are beneficial.
They have used dozens of plants and herbs with phytoestrogenic activity. Herbalists and native cultures have used many of these herbs for hundreds of years. Some phytoestrogens are essential to hormone regulation, some trigger release of various chemical messengers, and still others assist in regulation of fatty acid metabolism. They not only increase breast size, but they minimize symptoms of menopause, relieve constipation, control diabetes, reduce cholesterol, and prevent breast cancer. In another study in the Journal of the American Menopause Society, a daily diet containing 34 milligrams of phytoestrogens in 20 grams of soy protein significantly lowered cholesterol.