Isoflavone Research Initiative

The most recent findings on soy and isoflavones were presented in Washington DC on the occasion of the 9^th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment (October 16-19, 2010). A major part of the topics was dedicated to safety and health benefits in menopausal women, and to the issue of soy and breast cancer.

Dr. James Elliott (DSM Nutritional Products Inc., Parsippany, New Jersey, USA) presented the results of a randomized, placebo-controlled trial on the effect of genistein on the frequency and severity of menopausal hot flushes (Elliott et al. 2010; Evans et al. 2010). The 12-week trial was made in 84 postmenopausal women reporting at least 40 hot flushes per week. Participants received either a single dose of 30 mg of genistein or placebo (each group n = 42). Severity was addressed by the Greene Climacteric Scale.

The intake of genistein and the soy food status was supervised through analyses of genistein in urine. In the placebo group genistein was detected with 0.04 mg/dl before and with 0.03 mg/dl after the trial. In the genistein group the starting values were higher, but a significant change from 0.65 to 178.8 mg/ml was detected.

Subjects completing the study on genistein reported a significant decrease in the average number of hot flushes at week 8 (p = 0.045) and week 12 (p = 0.015) compared to completers on placebo. Subjects on genistein also demonstrated a greater percent reduction of hot flushes from baseline to weeks 4, 8 and 12 compared to placebo (31 vs. 16 % at week 4 (p = 0.066), 40 vs. 24 % at week 8 (p = 0.062), and 44 vs. 22 % at week 12 (p = 0.027)).

Endometrial thickness and levels of FSH and estradiol were measured as parameters of safety of application. As in all available clinical trials where these parameters were determined (without exception), no “estrogenic” effects of genistein were found.

References

Elliott J, Evans M, Sharma P, Berman R and Guthrie N (2010). The effect of genistein on menopause symptom management in healthy postmenopausal women: A multicenter, randomized, placebo-controlled study. 9^th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment, Washington DC, 16-19 October.

Evans M, Elliott J, Sharma P, Berman R and Guthrie N (2010). The effect of synthetic genistein on menopause symptom management in healthy postmenopausal women: A multicenter, randomized, placebo-controlled study. Maturitas (e-ahead of print, Dec. 14).