(HealthDay News) – Long-term dietary supplementation with isoflavone-rich soy protein does not appear to improve the global cognition of healthy postmenopausal women.

Victor W. Henderson, MD, of Stanford University in California, and colleagues conducted a randomized, controlled, double-blind trial involving 350 healthy postmenopausal women, aged 45–92 years, who received either daily 25g of isoflavone-rich soy protein, comparable to that of traditional Asian diets, or a milk protein-matched placebo. The primary outcome measure was change from baseline on global cognition, which was determined using a weighted sum of 14 different neuropsychological test scores. The intent-to-treat analysis included 313 women.

After 2.5 years, the researchers noted no statistically significant between-group difference in global cognition change from baseline (0.42 and 0.31 for isoflavone- and placebo-treated groups, respectively). However, women in the isoflavone-treated group had a greater improvement in visual memory factor. Individual test scores and a subgroup analysis of younger postmenopausal women did not show statistically significant differences between the groups.

“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,” the authors write.

The soy research and product development company Solae provided study products without charge.

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