phytoestrogens and Cognition-Disorders

Neuroprotective effects of phytoestrogen compounds (found in soy) have been demonstrated in animal research and cell culture studies. In particular, phytoestrogens have been shown to reduce Alzheimer's Disease (AD) related pathology, potentially alleviating risk of AD progression. In addition to their antioxidant properties, soy products also have the ability to affect cognition via interaction with estrogen receptors. However, observational studies and randomised controlled trials in humans have resulted in inconclusive findings within this domain. There are several possible reasons for these discrepant data. Studies which report no effect of phytoestrogens on cognition have mainly been carried out in European cohorts, with an average low dietary consumption. In contrast, investigation of Asian populations, with a higher general intake of tofu (a non-fermented soy product) have shown negative associations with cognitive function in those over the age of 65. Consideration of type of soy product is important, as in the latter sample, protective effects of tempe (fermented soy) were also observed. Limited data provide evidence that effects of phytoestrogens on cognition may be modified by dosage, duration of consumption and cognitive test used. Additionally, characteristics of the study population including age, gender, ethnicity and menopausal status appear to be mediating variables. Phytoestrogen treatment interventions have also shown time-limited positive effects on cognition. These findings are consistent with estrogen treatment studies, where initial positive short-term cognitive effects may occur, which reverse with long-term continuous use in elderly women. Well controlled, large scale studies are needed to assess the effects of phytoestrogens on the aging brain and provide further understanding of this association.

Topics: Alzheimer Disease; Brain; Cognition; Cognition Disorders; Female; Glycine max; Humans; Isoflavones; Male; Memory; Neuroprotective Agents; Phytoestrogens

Review controlled clinical trials of isoflavones and amino acid preparation effects on hot flashes and at least one other symptom including mood, sleep, pain, and cognitive function that women report during the menopausal transition and early postmenopause.. An experienced reference librarian searched PubMed/Medline, CINAHL Plus, PsycInfo, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, EMBASE, AMED, and Alt-Health Watch for English-language randomized controlled trials between 2004 and July 2011. Seventeen trials of isoflavones and amino acid effects on hot flashes and one additional symptom were identified.. In five trials of soy isoflavone preparations, two (6g soy germ extract and 25 g soy protein in soy nuts) significantly decreased hot flashes, but no other symptoms. In the seven trials of other isoflavones, six significantly reduced hot flashes; in addition, red clover (80 mg) significantly reduced mood symptoms; Rexflavone (350 mg) for women with Kupperman Index>20 significantly reduced sleep symptoms; two trials had significant reductions for pain: isoflavone powder (90 mg) and red clover (80 mg). The only trial in this systematic review that significantly reduced cognitive symptoms was red clover (80 mg). In one trial, red clover isoflavone (80 mg/day) significantly relieved hot flashes, mood, pain, and cognitive symptoms. Amino acids yielded no significant results. Equol supplements of 30 mg/day for non-Equol producing women significantly reduced mood symptoms in one trial. The magnolia bark extract combination significantly reduced hot flashes, mood, and sleep symptoms.. Isoflavone trials yielded significant reductions on hot flashes and co-occurring symptoms during the menopausal transition and postmenopause, but studies require replication with larger sample sizes and attention to measurement of outcomes.

Topics: Affect; Amino Acids; Cognition Disorders; Female; Hot Flashes; Humans; Isoflavones; Menopause; Pain; Phytoestrogens; Postmenopause; Sleep Wake Disorders

Topics: Aged; Aging; Alcohol Drinking; Antioxidants; Avitaminosis; Blood Glucose; Cognition Disorders; Dementia; Estrogens, Non-Steroidal; Humans; Inflammation; Isoflavones; Phytoestrogens; Plant Preparations; Quality of Life

This methodological paper presents both a scientific rationale and a methodological approach for investigating the effects of resveratrol supplementation on mood and cognitive performance in postmenopausal women. Postmenopausal women have an increased risk of cognitive decline and dementia, which may be at least partly due to loss of beneficial effects of estrogen on the cerebrovasculature. We hypothesise that resveratrol, a phytoestrogen, may counteract this risk by enhancing cerebrovascular function and improving regional blood flow in response to cognitive demands. A clinical trial was designed to test this hypothesis.. Healthy postmenopausal women were recruited to participate in a randomised, double-blind, placebo-controlled (parallel comparison) dietary intervention trial to evaluate the effects of resveratrol supplementation (75 mg twice daily) on cognition, cerebrovascular responsiveness to cognitive tasks and overall well-being. They performed the following tests at baseline and after 14 weeks of supplementation: Rey Auditory Verbal Learning Test, Cambridge Semantic Memory Battery, the Double Span and the Trail Making Task. Cerebrovascular function was assessed simultaneously by monitoring blood flow velocity in the middle cerebral arteries using transcranial Doppler ultrasound.. This trial provides a model approach to demonstrate that, by optimising circulatory function in the brain, resveratrol and other vasoactive nutrients may enhance mood and cognition and ameliorate the risk of developing dementia in postmenopausal women and other at-risk populations.

Topics: Affect; Aged; Aged, 80 and over; Cerebrovascular Circulation; Clinical Protocols; Cognition; Cognition Disorders; Dementia; Dietary Supplements; Double-Blind Method; Female; Health Status; Humans; Mental Health; Middle Aged; Neuropsychological Tests; New South Wales; Phytoestrogens; Postmenopause; Regional Blood Flow; Research Design; Resveratrol; Risk Factors; Stilbenes; Time Factors; Treatment Outcome; Ultrasonography, Doppler, Transcranial

To assess the effects of 6 weeks of treatment with soy supplements on mood, menopausal symptoms, and cognition in postmenopausal women not taking other forms of hormone therapy.. In a double-blind, placebo-matched parallel groups study, 50 postmenopausal women (aged 51-66 y) were randomly allocated to receive daily treatment with a soy supplement (Novasoy, 60 mg total isoflavone equivalents/day) or matching placebo capsules. They were tested at baseline before treatment began and after 6 weeks of treatment in tests of attention, memory, and frontal lobe function, and completed questionnaires to assess sleepiness, mood, and menopausal symptoms.. After 6 weeks of treatment, there was a significant (P < 0.02) reduction in somatic menopausal symptoms in the group taking soy supplements, but there were no other significant effects of soy on menopausal symptoms or mood. On the test of nonverbal short-term memory, the soy group showed greater improvement than the placebo group (P < 0.03), but there were no effects of soy on long-term memory, category generation, or sustained attention. However, the soy treatment produced significantly better performance on the two tests of frontal lobe function, those of mental flexibility (simple rule reversal, P < 0.05; complex rule reversal, P < 0.03) and of planning ability (P < 0.05).. The results suggest that the main improvement after 6 weeks of soy supplementation was in frontal lobe function. Significant improvements in the same three measures of frontal lobe function were previously found after 12 weeks of soy supplements in postmenopausal women. The effects of soy on memory seem less robust.

Topics: Aged; Cognition Disorders; Double-Blind Method; Drug Administration Schedule; Estrogen Replacement Therapy; Female; Frontal Lobe; Humans; Middle Aged; Phytoestrogens; Phytotherapy; Postmenopause; Soybean Proteins; Surveys and Questionnaires; Treatment Outcome

Elevated levels of β-amyloid (Aβ) in the brains being a hallmark of Alzheimer's disease have been believed to play a critical role in the cognitive dysfunction that occurs in Alzheimer's disease. Recent evidence suggests that Aβ induces neuronal apoptosis in the brain and in primary neuronal cultures. In this study, we investigated the effects of puerarin, a phytoestrogen isolated from Pueraria lobata, on cognitive function and neuronal apoptosis in the intrahippocampal injection of Aβ rats and its mechanism of action. The results show the intrahippocampal injection of Aβ induced a spatial memory deficit, apoptosis, and caspase-9 activation in hippocampal neurons. Puerarin treatment ameliorated Aβ(1-42)-induced cognitive impairment and reversed the increase of apoptosis in the hippocampus. The attenuation is associated with the activation of Akt and phosphorylation of Bad. These results suggest that puerarin may be an anti-Alzheimer's disease candidate drug to suppress both Alzheimer's disease-related neuronal cell apoptosis and dysfunction of the memory system.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Apoptosis; Apoptosis Regulatory Proteins; Cells, Cultured; Cognition Disorders; Dose-Response Relationship, Drug; Enzyme Activation; Gene Expression Regulation; Hippocampus; Isoflavones; Male; Maze Learning; Memory Disorders; Nerve Tissue Proteins; Neurons; Neuroprotective Agents; Phosphorylation; Phytoestrogens; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; RNA, Messenger