PT  - JOURNAL ARTICLE
AU  - V.W. Henderson
AU  - J.A. St. John
AU  - H.N. Hodis
AU  - N. Kono
AU  - C.A. McCleary
AU  - A.A. Franke
AU  - W.J. Mack
TI  - Long-term soy isoflavone supplementation and cognition in women
AID  - 10.1212/WNL.0b013e318258f822
DP  - 2012 Jun 05
TA  - Neurology
PG  - 1841--1848
VI  - 78
IP  - 23
4099  - http://n.neurology.org/content/78/23/1841.short
4100  - http://n.neurology.org/content/78/23/1841.full
SO  - Neurology2012 Jun 05; 78
AB  - Objective: To determine the cognitive effects of long-term dietary soy isoflavones in a daily dose comparable to that of traditional Asian diets. Methods: In the double-blind Women's Isoflavone Soy Health trial, healthy postmenopausal women were randomly allocated to receive daily 25 g of isoflavone-rich soy protein (91 mg of aglycone weight of isoflavones: 52 mg of genistein, 36 mg of daidzein, and 3 mg glycitein) or milk protein−matched placebo. The primary cognitive endpoint compared between groups at 2.5 years was change from baseline on global cognition, a composite of the weighted sum of 14 neuropsychological test score changes. Secondary outcomes compared changes in cognitive factors and individual tests. Results: A total of 350 healthy postmenopausal women aged 45–92 years enrolled in this trial; 313 women with baseline and endpoint cognitive test data were included in intention-to-treat analyses. Adherence in both groups was nearly 90%. There was no significant between-group difference on change from baseline in global cognition (mean standardized improvement of 0.42 in the isoflavone group and 0.31 in the placebo group; mean standardized difference 0.11, 95% confidence interval [CI] −0.13 to 0.35). Secondary analyses indicated greater improvement on a visual memory factor in the isoflavone group (mean standardized difference 0.33, 95% CI 0.06–0.60) but no significant between-group differences on 3 other cognitive factors or individual test scores, and no significant difference within a subgroup of younger postmenopausal women. Conclusion: For healthy postmenopausal women, long-term dietary soy isoflavone supplementation in a dose comparable to that of traditional Asian diets has no effect on global cognition but may improve visual memory. Classification of evidence: This study provides Class I evidence that long-term dietary supplementation with isoflavone-rich soy protein does not improve global cognition of healthy postmenopausal women. CI=confidence interval; ISP=isoflavone-rich soy protein; WISH=Women's Isoflavone Soy Health