Paradoxically, estrogen can be both a beneficial and a harmful molecule.
The main beneficial effects of estrogen include its roles in
programming the breast and uterus for sexual reproduction,
controlling cholesterol production in ways that limit the buildup of plaque in the coronary arteries, and
preserving bone strength by helping to maintain the proper balance between bone buildup and breakdown.
Unfortunately, in addition to these important beneficial effects, estrogen can also be harmful. The most serious problem arises from the ability of estrogen to promote the proliferation of cells in the breast and uterus. Although this ability to stimulate cell proliferation is one of estrogen’s normal roles, it can also increase a woman’s chance of developing breast or uterine cancer.