Human Estrogen is the natural means of preventing bone loss before menopause in women. The huge drop in estrogen levels during menopause leads to increased bone loss during and after menopause.
Estrogen stimulates the formation of Osteoblasts (the cells that make new bone). Estrogen lengthens the lifespan of Osteoblasts and Osteocytes (the cells that live in and maintain bone). Estrogen supresses the formation and activation of Osteoclasts (the cells that eat bone away).
Estrogen is used in post-menopausal and peri-menopausal women as Modern “Hormone Replacement Therapy”. The lower doses, adopted about 15 years ago, do not carry the occasional heart risk of the older doses.
Women who use HRT for menopausal symptoms get the added benefit of better Bone Health. Many years use of the old high dose HRT carried an increased risk of breast cancer. That risk appears less with the new lower dose HRT.
Some women use phyto-estrogens from plant sources. For most phyto-estrogens, we simply don’t know whether the breast cancer risk is higher or lower than with human estrogen.
Tamoxifen is the only phyto-estrogen proven to decrease the risk of breast cancer. Unfortunately, it has no demonstrated benefit to Bone Health. Raloxifene helps both breast and bone. More next time.
Jay Ginther, MD