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Long-term soy isoflavone supplementation and cognition in women: a randomized, controlled trial.

Abstract

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.

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  • Authors+Show Affiliations

    ,

    Departments of Health Research and Policy (Epidemiology) and Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.

    , , , , , ,

    Source

    Neurology 78:23 2012 Jun 05 pg 1841-8

    MeSH

    Aged
    Aged, 80 and over
    Cognition
    Dietary Supplements
    Double-Blind Method
    Female
    Humans
    Isoflavones
    Memory
    Middle Aged
    Postmenopause
    Soybean Proteins
    Time Factors
    Women's Health

    Pub Type(s)

    Comparative Study
    Journal Article
    Randomized Controlled Trial
    Research Support, N.I.H., Extramural

    Language

    eng

    PubMed ID

    22665144

    Citation

    Henderson, V W., et al. "Long-term Soy Isoflavone Supplementation and Cognition in Women: a Randomized, Controlled Trial." Neurology, vol. 78, no. 23, 2012, pp. 1841-8.
    Henderson VW, St John JA, Hodis HN, et al. Long-term soy isoflavone supplementation and cognition in women: a randomized, controlled trial. Neurology. 2012;78(23):1841-8.
    Henderson, V. W., St John, J. A., Hodis, H. N., Kono, N., McCleary, C. A., Franke, A. A., & Mack, W. J. (2012). Long-term soy isoflavone supplementation and cognition in women: a randomized, controlled trial. Neurology, 78(23), pp. 1841-8. doi:10.1212/WNL.0b013e318258f822.
    Henderson VW, et al. Long-term Soy Isoflavone Supplementation and Cognition in Women: a Randomized, Controlled Trial. Neurology. 2012 Jun 5;78(23):1841-8. PubMed PMID: 22665144.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Long-term soy isoflavone supplementation and cognition in women: a randomized, controlled trial. AU - Henderson,V W, AU - St John,J A, AU - Hodis,H N, AU - Kono,N, AU - McCleary,C A, AU - Franke,A A, AU - Mack,W J, AU - ,, PY - 2012/6/6/entrez PY - 2012/6/6/pubmed PY - 2012/8/10/medline SP - 1841 EP - 8 JF - Neurology JO - Neurology VL - 78 IS - 23 N2 - 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. SN - 1526-632X UR - https://www.unboundmedicine.com/medline/citation/22665144/Long_term_soy_isoflavone_supplementation_and_cognition_in_women:_a_randomized_controlled_trial_ L2 - http://www.neurology.org/cgi/pmidlookup?view=long&pmid=22665144 DB - PRIME DP - Unbound Medicine ER -