Estrogen is a hormone that activates bone-forming cells and prevents calcium loss and bone breakdown. During menopause, estrogen levels decrease. Insufficient amounts of estrogen may accelerate bone breakdown and inhibit the body's ability to create new bone, thereby leading to bone loss and possibly osteoporosis. Various treatments have been developed to decrease bone loss in post-menopausal women. Actonel, for example, is an FDA-approved drug used to help prevent bone loss.~Phytoestrogens are plant compounds with a structure similar to estrogen. They have also been shown to help reduce the negative effects of menopause. Isoflavones are a particular type of phytoestrogens that are found in soy plants and may act like estrogen in providing possible protection against bone loss. This study will compare the effects of isoflavones (including genistein, a type of isoflavone) versus Actonel on calcium absorption and bone loss in post-menopausal women.~Participants in this double-blind cross-over study will first complete a screening process, which will include answering questions about their health habits, medical history, physical activity, and food patterns. They will then eat one soy bar daily for 3 days. On Day 4, a urine sample will be taken to assess their ability to metabolize phytoestrogen from soybeans. Participants will be randomly assigned to a specific treatment order. Participants will receive 1-4 unique soy isoflavones, followed by Actonel. Treatment phases will be separated by a 50-day washout period. All participants will also take calcium and vitamin D supplements throughout the study. Assessments will include bone density measurements, calcium absorption tests, and blood and urine tests. The study will last approximately 2.5 years.
Estrogen is a hormone that helps prevent calcium loss and bone breakdown. During menopause, estrogen levels decrease. Insufficient amounts of estrogen may lead to bone loss and possibly osteoporosis. Isoflavones are natural compounds found in soy plants that may help provide protection against bone loss. This study will evaluate the effect of soy isoflavones on calcium absorption and bone loss in post menopausal women.