Gender Differences in Phytoestrogens and the Relationship with Speed of Processing in Older Adults: A Cross-Sectional Analysis of NHANES, 1999-2002.

Sex hormone changes in adults are known to play a part in aging, including cognitive aging. Dietary intake of phytoestrogens can mimic estrogenic effects on brain function. Since sex hormones differ between genders, it is important to examine gender differences in the phytoestrogen-cognition association. Therefore, the goal of this study is to examine the relationship between urinary phytoestrogens and speed of processing (SOP) and the variation of the association between genders in older adults. Participants were drawn from the 1999-2002 National Health and Nutrition Examination Survey and included 354 individuals aged 65-85 years old. General linear models (GLMs) were used to test for significant gender differences in the relationship between phytoestrogens and SOP. Results from the GLMs showed significant gender differences in the relationship between genistein and SOP. Higher levels of genistein were associated with better SOP in women. This relationship was reversed in men: higher genistein levels were associated with worse performance. Results indicate that there are distinct gender differences in the relationship between genistein and SOP. These results emphasize the importance of considering gender differences when devising dietary and pharmacologic interventions that target phytoestrogens to improve brain health.

The relationship between phytoestrogens and speed of processing.

OBJECTIVE: This study examined the cross-sectional association between phytoestrogens and speed of processing. We hypothesized that higher levels of phytoestrogens would be related to better cognitive performance among older women. METHODS: Participants were from the National Health and Nutrition Examination Survey and consisted of 200 older women (M = 74.4 y). Stepwise regressions examined indicators of speed of processing, measured by the Digit Symbol Substitution Test. Isoflavones, lignans, and individual phytoestrogens were added to the regression after including covariates of age, education, race, smoking, and creatinine. Isoflavones were further broken into quartiles among the sample to further evaluate the nature of the curvilinear association. RESULTS: Results showed a relationship between cognition and lignans, explaining 3.8% of the variance after including the covariates, indicating fewer lignans were associated with better speed of processing (P < 0.001). A significant curvilinear relationship with isoflavones explained 1.3% additional variance (P < 0.001). The moderate-high, low-moderate, and the lowest quartile of isoflavones were associated with better cognition, whereas the highest amount was associated with worse speed of processing. Among the individual phytoestrogens, only enterodiol accounted for 4.4% additional variance after taking into account covariates and indicated a negative association with cognition (P = 0.03). CONCLUSIONS: Results suggest that moderate levels of isoflavones, but not lignans, may be associated with better speed of processing. Caution must remain for high isoflavone amounts due to the negative association with cognition. Given the results, phytoestrogens have the potential to be an intervention target for older females' cognition. To become a viable intervention, further research is needed.

The Efficacy of InSight Cognitive Training to Improve Useful Field of View Performance: A Brief Report.

OBJECTIVE: It is well established that cognitive speed of processing training (SOPT) improves Useful Field of View (UFOV) performance and transfers to enhanced performance of instrumental activities of daily living, including driving. InSight is a recently developed version of SOPT formatted for self-administration by older adults with exercises translated into a gaming format. The goal was to examine whether InSight training improves UFOV performance. METHOD: Participants ranged in age between 59-95 years and were randomized to InSight cognitive training or a control condition. Cognitive performance and self-perceptions were measured pre- and post-training, or for controls, after an equivalent delay. Participants completed training twice a week over a 12-week period with the goal of completing 20 sessions. RESULTS: Participants randomized to InSight training experienced greater improvements in their UFOV performance relative to the control condition, F(1, 58) = 4.26, p = .043, but no changes in cognitive self-perceptions were found. CONCLUSIONS: The InSight program is a viable tool for enhancing older adults' UFOV performance. Future research should examine if training gains from the program endure and transfer to improved everyday function.

Longitudinal differences in cognitive functioning among older adults with and without heart failure.

OBJECTIVE: Secondary data analyses were conducted to examine cognitive function and longitudinal cognitive decline among older adults with and without heart failure (HF). METHOD: Data from the Advanced Cognitive Training for Independent and Vital Elderly study were used to compare baseline (N = 2,790) and longitudinal (n = 692) changes in memory, reasoning, and speed of processing performance among participants (M age = 73.61, SD = 5.89) who self-reported HF at baseline, developed HF over time, or never reported HF. RESULTS: At baseline, there were differences in memory and speed of processing with participants who never reported HF performing better than those who reported developing HF over time, and those who reported HF at baseline performing the worst (ps < .05). Longitudinally, participants with self-reported HF at baseline showed declines in reasoning over time. DISCUSSION: The results indicate that cognitive difficulties in memory and speed may occur prior to a HF diagnosis, while those with HF may experience steeper declines in reasoning as measured by word series test.