The effects of dietary supplementation with isoflavones from red clover on cognitive function in postmenopausal women

Howes, Jan B; Bray, Katharine; Lorenz, Laura S.; Smerdely, Peter; Howes, Laurence G.

doi:10.1080/13697130310001651490

Cited by 47 publications

(69 citation statements)

References 16 publications

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“…Previous agents for the improvement of cognition all have side effects such as nausea, vomiting, etc. 19) Recently, it has been reported that the BF-7, a protein in the natural extract from Bombyx mori, exerted significant neuroprotection, functionally and physiologically. 20) For example, Lee et al showed that BF-7 protected SK-N-SH cells, human neuroblastoma cells, from reactive oxidative stress.…”

Section: Introductionmentioning

confidence: 99%

Neuroprotection and Enhancement of Learning and Memory by BF-7

Kim

Kang

Lee

et al. 2005

JOURNAL OF HEALTH SCIENCE

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Section: Introductionmentioning

confidence: 99%

Neuroprotection and Enhancement of Learning and Memory by BF-7

Kim

Kang

Lee

et al. 2005

JOURNAL OF HEALTH SCIENCE

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“…Additionally, both Casini et al (84) and Santos et al (91) reported multiple t tests without any apparent correction for type I error. Howes et al (85) also carried out a large number of tests on a small sample (n 30) initially reporting a series of significant effects. However, as an illustration of good practice, these disappeared after the authors statistically accounted for type I error.…”

Section: Assessment Of Cognitive Performance In Existing Studiesmentioning

confidence: 99%

Cognitive tests used in chronic adult human randomised controlled trial micronutrient and phytochemical intervention studies

et al. 2010

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In recent years there has been a rapid growth of interest in exploring the relationship between nutritional therapies and the maintenance of cognitive function in adulthood. Emerging evidence reveals an increasingly complex picture with respect to the benefits of various food constituents on learning, memory and psychomotor function in adults. However, to date, there has been little consensus in human studies on the range of cognitive domains to be tested or the particular tests to be employed. To illustrate the potential difficulties that this poses, we conducted a systematic review of existing human adult randomised controlled trial (RCT) studies that have investigated the effects of 24 d to 36 months of supplementation with flavonoids and micronutrients on cognitive performance. There were thirty-nine studies employing a total of 121 different cognitive tasks that met the criteria for inclusion. Results showed that less than half of these studies reported positive effects of treatment, with some important cognitive domains either under-represented or not explored at all. Although there was some evidence of sensitivity to nutritional supplementation in a number of domains (for example, executive function, spatial working memory), interpretation is currently difficult given the prevailing 'scattergun approach' for selecting cognitive tests. Specifically, the practice means that it is often difficult to distinguish between a boundary condition for a particular nutrient and a lack of task sensitivity. We argue that for significant future progress to be made, researchers need to pay much closer attention to existing human RCT and animal data, as well as to more basic issues surrounding task sensitivity, statistical power and type I error.

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“…9 Adverse outcomes are occasionally described, 13 and observational findings raise concern of cognitive harm. 16,17 Given widespread interests in soy products among postmenopausal women 5,6 and controversial findings on cognitive function, [7][8][9][10][11][12][13][14][15] we sought to examine the long-term cognitive efficacy of soy isoflavones in the Women's Isoflavone Soy Health (WISH) trial. This study of healthy midlife and older women was designed to assess the effects of dietary supplementation with isoflavone-rich soy protein (ISP) containing naturally occurring isoflavones in quantities within the upper range of traditional Asian diets.…”

Section: Classification Of Evidencementioning

confidence: 99%

“…Improved cognition is reported in some clinical trials [7][8][9][10] but not others. [11][12][13][14][15] Cognitive benefit is possibly restricted to younger postmenopausal women 6 or to specific cognitive domains. 9 Adverse outcomes are occasionally described, 13 and observational findings raise concern of cognitive harm.…”

Section: Classification Of Evidencementioning

confidence: 99%

“…9,14 In a search that included PubMed and the Cochrane Central Register of Controlled Trials electronic databases (with search terms for isoflavone, soya, or tofu combined with memory or cognition, without restriction on publication date or language), we identified 9 randomized double-blind placebocontrolled trials in midlife or later-life women with objective cognitive endpoints. [7][8][9][10][11][12][13][14][15] The trials identified were of shorter duration than WISH with lower power to detect potential effects of study interventions. The ISP supplement in the WISH trial, which provides principal isoflavones in a soy proteinϪbased Asian diet, was similar in composition and dose to supplements in most trials.…”

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confidence: 99%

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Long-term soy isoflavone supplementation and cognition in women

Henderson

John²,

Hodis³

et al. 2012

Neurology

107

106

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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 proteinϪmatched 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] Ϫ0.13 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. Isoflavones are plant-derived diphenolic micronutrients with structural similarities to steroidal estrogens. Soybeans (Glycine max) and soy-based food products are the major dietary source of isoflavones. The primary soy isoflavones, genistin, daidzin, and glycitin, are hydrolyzed within the intestines to their respective aglycones (genistein, daidzein, and glycitein) before systemic absorption. Classification of evidence:

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The effects of dietary supplementation with isoflavones from red clover on cognitive function in postmenopausal women

Abstract: Isoflavone supplementation does not appear to have major short-term effects on cognitive function in postmenopausal women. However, further clinical trials are required to determine whether small effects or long-term effects on cognitive function occur during isoflavone supplementation.

Cited by 47 publications

References 16 publications

Neuroprotection and Enhancement of Learning and Memory by BF-7

Neuroprotection and Enhancement of Learning and Memory by BF-7

Cognitive tests used in chronic adult human randomised controlled trial micronutrient and phytochemical intervention studies

Long-term soy isoflavone supplementation and cognition in women

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