Soy Isoflavone Supplementation Demonstrates Ability To Reduce Bone Loss In Perimenopausal Women

James Meschino DC, MS, ROHP

There has been much debate as to whether or not soy isoflavones, which act as weak estrogens in the body, have sufficient estrogenic activity to help prevent demineralization of bone when a woman’s own estrogen production declines during menopause. Estrogen helps to keep calcium in bone up until the menopausal years, at which time the drop-off in estrogen production is known to contribute to the development of postmenopausal osteoporosis. In the U.S., one in four women demonstrate osteoporosis early in the postmenopausal years. In a randomized study involving 69 perimenopausal women, the group that received 24 weeks of continual isoflavone-rich soy supplementation demonstrated a favorable effect on preventing bone loss versus the control groups, which were given either whey protein supplementation or isoflavone-poor soy supplementation (containing only 4.4 mg per day). This study convincingly demonstrated that a daily soy intake yielding 80.4 mg of isoflavones provides an estrogenic effect on bone, sufficient to slow or prevent its demineralization. Soy isoflavones studied most intensively for their phytoestrogen properties include genistein and diadzein. Larger studies of this type are necessary to confirm these findings, however results from this preliminary trial agree with epidemiological evidence and animal studies performed to date, all of which indicate that soy isoflavones support bone mineral density in postmenopausal women and oopherectomized animals.

Reference:

Alekel DL et al, Isoflavone-rich soy protein isolate attenuates bone loss in the lumbar spine of perimenopausal women. Am J ClinNutr. 2000;72 : 844-852