MIAMI—According to a recent single-center, randomized, placebo-controlled, double blind clinical trial, conducted from July 1, 2004, to March 31, 2009, 200 mg/d of soy isoflavones tablets for two years did not prevent bone loss or menopausal symptoms (Arch Intern Med. 2011;171(15):1363-1369).
In this study, women, aged 45 to 60 years within five years of menopause and with a bone mineral density (BMD) T score of –2.0 or higher in the lumbar spine or total hip, were randomly assigned to receive 200 mg/d of soy isoflavone tablets or placebo. The primary outcome was changes BMD in the lumbar spine, total hip and femoral neck at the two-year follow-up. Secondary outcomes included changes in menopausal symptoms, vaginal cytologic characteristics, N -telopeptide of type I bone collagen, lipids and thyroid function.
After two years, no significant differences were found between the participants receiving soy tablets (n=122) and those receiving placebo (n=126) regarding changes in BMD in the spine, the total hip or the femoral neck. A significantly larger proportion of participants in the soy group experienced hot flashes and constipation compared with the control group. No significant differences were found between groups in other outcomes.
