A very recent study has investigated once again the potential benefits of soy isoflavones in regard to bone protection and vasomotor symptoms . A total of 248 women aged 45–60 years within 5 years of menopause and with a bone mineral density [i]T[/i]-score of -2.0 or higher in the lumbar spine or total hip were randomly assigned, in equal proportions, to receive daily soy isoflavone tablets, 200 mg, or placebo. After 2 years, no significant differences were found between the participants receiving soy tablets and those receiving placebo regarding changes in bone mineral density in the spine (-2.0% and -2.3%, respectively), the total hip (-1.2% and -1.4%, respectively), or the femoral neck (-2.2% and -2.1%, respectively). A significantly larger proportion of participants in the soy group experienced hot flushes and constipation compared with the control group. No significant differences were found between groups in other outcomes. These clear-cut results from an NIH-funded, double-blind, placebo-controlled, randomized study were summarized as follows: ‘The daily administration of tablets containing 200 mg of soy isoflavones for 2 years did not prevent bone loss or menopausal symptoms.’ In an accompanying Editorial, Drs Grady and Newton expressed their concrete view by saying that ‘despite the efforts of many investigators to find alternatives to estrogen, no therapy, to date, has approached the efficacy of standard-dosage estrogen for treatment of vasomotor symptoms’ .
Department of Medicine T, Ichilov Hospital, Tel-Aviv, Israel
Levis S, Strickman-Stein N, Ganjei-Azar P, et al. Soy isoflavones in the prevention of menopausal bone loss and menopausal symptoms. Arch Intern Med 2011;171:1363-1369.
Newton KM, Grady D. Comment on Levis S et al study. Arch Intern Med 2011;171:1369-70.
Levis S, Strickman-Stein N, Doerge DR, Krischer J. Design and baseline characteristics of The Soy Phytoestrogens As Replacement Estrogen (SPARE) Study A clinical trial of the effects of soy isoflavones in menopausal women. Contemp Clin Trials 2010;31:293-302.
Carmignani LO, Pedro AO, Costa-Paiva LH, Pinto-Neto AM. The effect of dietary soy supplementation compared to estrogen and placebo on menopausal symptoms: a randomized controlled trial. Maturitas 2010;67:262-9.
Aso T. Equol improves menopausal symptoms in Japanese women. J Nutr 2010;140:1386-9S.