THE EFFECT OF DIETARY SOY SUPPLEMENTATION ON HOT FLUSHES

Objective: To assess the effect of daily dietary supplementation of so y protein isolate powder on hot flushes in postmenopausal women. Metho ds: We carried out a double-blind, parallel, multicenter, randomized p lacebo-controlled trial of 104 postmenopausal women. Fifty-one patient s (age range 48-61 years) took 60 g of isolated soy protein daily and 53 patients (age range 45-62 years) took 60 g of placebo (casein) dail y. The study lasted 12 weeks. Using analysis of covariance, we analyze d changes from baseline in mean number of moderate to severe hot hushe s (including night sweats) during treatment. Results: Soy was signific antly superior to placebo (P < .01 in reducing the mean number of hot flushes per 24 hours after 4, 8, and 12 weeks of treatment. In particu lar, women taking soy had a 26% reduction in the mean number of hot fl ushes by week 3 and a 33% reduction by week 4 (P < .001 by the Wilcoxo n exact test). By the end of the 12th week, patients taking soy had a 45% reduction in their daily hot flushes versus a 30% reduction obtain ed with the placebo (P < .01). The overall rates of adverse effects we re similar for soy and casein-placebo. Twenty-five patients dropped ou t of the study: II in the soy group and 14 in the placebo group. Gastr ointestinal side effects were the most common cause of premature withd rawal from the study (seven patients in each group). Conclusion: Soy p rotein isolate added daily to the diet substantially reduced the frequ ency of hot flushes in climacteric women. (C) 1998 by The American Col lege of Obstetricians and Gynecologists.