Effects of soy isoflavone supplementation on cognitive function in Chinese postmenopausal women: A double-blind, randomized, controlled trial

Department of Community and Family Medicine, School of Public Health, The Chinese University of Hong Kong, SAR.
Menopause (Impact Factor: 3.36). 05/2007; 14(3 Pt 1):489-99. DOI: 10.1097/GME.0b013e31802c4f4f
Source: PubMed

ABSTRACT To investigate whether soy-derived isoflavone extract improves performance in cognitive function and quality of life in Chinese postmenopausal women.
The study was a 6-month double-blind, randomized, placebo-controlled, parallel group trial. Participants were community-dwelling women aged 55 to 76 years; 191 eligible women were randomly assigned to receive a daily oral intake of 80 mg soy-derived isoflavones or an identical-appearing placebo for 6 months. Standardized neuropsychological tests of memory, executive function, attention, motor control, language, and visual perception and a global cognitive function assessment were administered face-to-face individually at baseline and at 6-months posttreatment. The validated Chinese version of the Short Form-36 was used for quality of life measurements.
Of the participants, 88% (168 women: 80 among the supplementation group and 88 among the placebo group) completed the trial. Intention-to-treat analysis, conducted for 176 participants with 6-month assessment results, revealed no significant differences in outcome measures between treatment groups. Subgroup analysis among the good compliers only (consumed at least 80% of the supplements or placebo; n = 168) and among the age groups younger or older than 65 years also indicated no significant differences for any outcome measures. Types of complaints of adverse events were similar in both treatment groups and included mainly gastrointestinal and musculoskeletal problems.
This 6-month trial indicates that 80-mg soy-derived isoflavone supplementation did not improve performance on standard neuropsychological tests and overall quality of life in generally healthy Chinese postmenopausal women.

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Available from: Suzanne C Ho, Sep 26, 2015
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    • "Noticeably, among all the reported intervention studies mentioned, only one of these was conducted in an Asian sample [18], whereas all the other studies were conducted in Western countries. "
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    ABSTRACT: Tofu is a soy product which is commonly consumed in Asian countries, such as China and Indonesia. Several studies found negative associations of high tofu consumption with cognitive function in older Asian populations. However, the effect of tofu on cognitive function remains disputed as it was not found in Western populations. In the present study, the effect of weekly tofu intake on cognitive performance was investigated in an observational cross sectional study of 517 Chinese elderly from Shanghai. Similar to earlier studies, results showed that a higher weekly intake of tofu was associated with worse memory performance using the Hopkins Verbal Learning Test (β = -0.10, p = 0.01) after controlling for age, gender, education, being vegetarian, and weekly intake of fruit/juice, green vegetables, and orange/red vegetables. Furthermore, among older elderly (≥68 years of age), high tofu intake increased the risk of cognitive impairment indicative of dementia (OR = 1.27, 95% CI = 0.99-1.64, p = 0.04), after adjusting for all covariates. Consumption of meat and green vegetables independently also reduced risk of dementia. To conclude, high intake of tofu was negatively related to cognitive performance among community-dwelling elderly in China. Similar findings were reported in Indonesia and in Japanese Americans in the US. These findings suggest that the effect of tofu on cognition in elderly should be further investigated.
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    • "However there are still conflicting data on the beneficial effects of soy isoflavones as some trials reported that it does not lead to cognitive improvements. A six-month trial indicates that 80 mg soy-derived isoflavones supplementation did not improve cognitive performance in generally healthy Chinese postmenopausal women [19]. Another double-blind randomized trial using soy protein containing isoflavones also reported negative finding [27]. "
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    ABSTRACT: We examined association between the changes in blood oxidative stress level/activity and the changes in memory performance in postmenopausal women receiving Tualang honey (TH). The verbal learning and memory performances of thirty nine postmenopausal women were assessed using the Malay version of the Auditory Verbal Learning Test (MVAVLT) and their oxidative stress levels/activities were determined using commercially available kits before and 16 weeks after TH supplementation. The plasma glutathione peroxidase (GPx) and catalase (CAT) activities were considerably increased but the 4-hydroxynonenal (4-HNE) level was notably decreased after 16 weeks of TH supplementation. There were positive correlations between the changes in plasma GPx and the changes in trial A6 scores (r = 0.48, P < 0.05) and between the changes in plasma CAT and the changes in recognition score (r = 0.32, P < 0.05). TH supplementation for 16 weeks reduced blood oxidative stress but most of the changes in blood oxidative stress level/activity were not significantly correlated with the changes in memory performance
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    • "c o m / l o c a t e / n e u t e r a ingredients may aide in healthy cognitive aging. For instance, reports of the effects of several commercially available dietary soy-based supplements (with mixed isoflavone contents/concentrations) on learning and memory processes from randomized controlled studies in aging women vary, reporting no effect (Basaria et al., 2009; Fournier et al., 2007; Henderson et al., 2012; Ho et al., 2007; Kreijkamp-Kaspers et al., 2004), some improvement (Casini et al., 2006; Duffy et al., 2003; File et al., 2005; Gleason et al., 2009; Kritz-Silverstein et al., 2003; Santos- Galduroz et al., 2010), or even an impairment (Kritz-Silverstein et al., 2003). In addition to isoflavone composition, methodological differences in age at the time of treatment, previous HRT use, cognitive domain tested , and length of treatment likely contribute to the conflicting findings among published reports (see also Sumien et al., 2013). "
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    ABSTRACT: The use of over-the-counter botanical estrogens containing isolated soy isoflavones, including genistein and daidzein, has become a popular alternative to traditional hormone therapies. Menopausal women use these products as an aide in healthy aging, including for the maintenance of cognitive function. The safety and efficacy of many of these commercial preparations remains unknown. Previous research in our lab found that treatment of ovariectomized (OVX) female Long-Evans rats with genistein impaired working memory in an operant delayed spatial alternation (DSA) task and response learning in a plus-maze, but enhanced place learning assessed in the plus-maze. The present study further examined the effects of isolated isoflavones on working memory and place learning by treating middle-aged (12-13month old) OVX female Long-Evans rats with S-equol, the exclusive enantiomer produced by metabolism of daidzein in the mammalian gut. S-equol binds selectively to ERβ with an affinity similar to that of genistein but has low transcriptional potency. For DSA testing, S-equol at 1.94, 0.97mg, or 0mg (sucrose control) was orally administered to animals daily, 30minutes before behavioral testing, and again both 4 and 8hours after the first treatment. Rats were tested on the DSA task following the first, morning dose. For place learning, rats received 0.97mgS-equol every 4hours during the light portion of the cycle beginning 48hours prior to behavioral testing (total exposure 8.7mgS-equol). S-equol treatment was largely without effect on the DSA and place learning tasks. This is the first study to test the behavioral effects of isolated S-equol in OVX rodents, and shows that, unlike genistein or estradiol, repeated daily treatment with this isoflavone metabolite does not alter learning and memory processes in middle-aged OVX rats.
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