  The effect of phytoestrogens on breast cancer  What are
phytoestrogens?  Phytoestrogens are a group of chemicals found
in plants that can act like the hormone estrogen. Estrogen is a
hormone necessary for childbearing and is involved with bone and
heart health in women. However, higher exposure to estrogens
over a lifetime is linked with increased breast cancer risk.
How do phytoestrogens act in the body?  There are many different
ways that phytoestrogens may work in the body. The chemical
structure of phytoestrogens is similar to estrogen, and they may
act as mimics (copies) of estrogen. On the other hand,
phytoestrogens also have effects that are different from those
of estrogen.  Working as estrogen mimics, phytoestrogens may
either have the same effects as estrogen or block estrogen's
effects. Which effect the phytoestrogen produces can depend on
the dose of the phytoestrogen. The phytoestrogen can act like
estrogen at low doses but block estrogen at high doses. Estrogen
activates a family of proteins