Journal Articles

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    ABSTRACT: The prevalence of childhood obesity in the United States has tripled since the 1980s and is strongly linked to the early onset of several metabolic diseases. Recent studies indicate that lower cognitive function may be another complication of childhood obesity. This review considers the research to date on the role of obesity and nutrition on childhood cognition and brain health. Although a handful of studies point to a maladaptive relationship between obesity and aspects of cognitive control, remarkably little is known regarding the impact of fat mass on brain development and cognitive function. Further, missing from the literature is the role of nutrition in the obesity-cognition interaction. Nutrition may directly or indirectly influence cognitive performance via several pathways including provision of key substrates for optimal brain health, modulation of gut microbiota, and alterations in systemic energy balance. However, in the absence of malnutrition, the functional benefits of specific nutrient intake on particular cognitive domains are not well characterized. Here, we examine the literature linking childhood obesity and cognition while considering the effects of nutritional intake. Possible mechanisms for these relationships are discussed and suggestions are made for future study topics. Although childhood obesity prevalence rates in some developed countries have recently stabilized, significant disparities remain among groups based on sex and socioeconomic status. Given that the elevated prevalence of pediatric overweight and obesity may persist for the foreseeable future, it is crucial to develop a comprehensive understanding of the influence of obesity and nutrition on cognition and brain health in the pediatric population.
    Monographs of the Society for Research in Child Development 12/2014; 79(4):51-71. · 5.50 Impact Factor
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    ABSTRACT: With the increasing prevalence of sedentary behaviors during childhood, a greater understanding of the extent to which excess adiposity and aerobic fitness relate to cognitive health is of increasing importance. To date, however, the vast majority of research in this area has focused on adiposity or fitness, rather than the possible inter-relationship, as it relates to cognition. Accordingly, this study examined the differential associations between body composition, aerobic fitness, and cognitive control in a sample of 204 (96 female) preadolescent children. Participants completed a modified flanker task (i.e., inhibition) and a switch task (i.e., cognitive flexibility) to assess two aspects of cognitive control. Findings from this study indicate that fitness and adiposity appear to be separable factors as they relate to cognitive control, given that the interaction of fitness and adiposity was observed to be nonsignificant for both the flanker and switch tasks. Fitness exhibited an independent association with both inhibition and cognitive flexibility whereas adiposity exhibited an independent association only with cognitive flexibility. These results suggest that while childhood obesity and fitness appear to both be related to cognitive control, they may be differentially associated with its component processes.
    Monographs of the Society for Research in Child Development 12/2014; 79(4). · 5.50 Impact Factor
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    ABSTRACT: To assess associations between adiposity and hippocampal-dependent and hippocampal-independent memory forms among prepubertal children. Prepubertal children (age 7-9 years; n = 126), classified as non-overweight (<85th percentile body mass index [BMI]-for-age [n = 73]) or overweight/obese (≥85th percentile BMI-for-age [n = 53]), completed relational (hippocampal-dependent) and item (hippocampal-independent) memory tasks. Performance was assessed with both direct (behavioral accuracy) and indirect (preferential disproportionate viewing [PDV]) measures. Adiposity (ie, percent whole-body fat mass, subcutaneous abdominal adipose tissue, visceral adipose tissue, and total abdominal adipose tissue) was assessed by dual-energy X-ray absorptiometry. Backward regression identified significant (P < .05) predictive models of memory performance. Covariates included age, sex, pubertal timing, socioeconomic status (SES), IQ, oxygen consumption, and BMI z-score. Among overweight/obese children, total abdominal adipose tissue was a significant negative predictor of relational memory behavioral accuracy, and pubertal timing together with SES jointly predicted the PDV measure of relational memory. In contrast, among non-overweight children, male sex predicted item memory behavioral accuracy, and a model consisting of SES and BMI z-score jointly predicted the PDV measure of relational memory. Regional, but not whole-body, fat deposition was selectively and negatively associated with hippocampal-dependent relational memory among overweight/obese prepubertal children. Copyright © 2014 Elsevier Inc. All rights reserved.
    The Journal of Pediatrics. 11/2014;
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    ABSTRACT: To assess the effect of a physical activity (PA) intervention on brain and behavioral indices of executive control in preadolescent children.
    Pediatrics. 09/2014;
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    ABSTRACT: Objective: To investigate the relationship between cognitive control and metabolic syndrome (MetS) risk factors in preadolescent children while controlling for aerobic fitness and weight status. Methods: Hierarchical regression analyses were conducted using aerobic fitness, demographic, and MetS risk-factor variables in a sample of 2nd- and 3rd-grade children (n = 139) who performed a modified version of a flanker task to assess cognitive control. Flanker performance was also compared between children that met no MetS risk-factor criteria (n = 70), and children who met 1 criterion or more (n = 69). Results: Regression analyses indicated that after controlling for demographic variables and fitness, HDL cholesterol exhibited an independent negative association with flanker reaction time (RT). Group comparisons further revealed that children with no risk factors demonstrated overall shorter RT than the at-risk group. In addition, at-risk children exhibited larger accuracy-interference scores (i.e., poorer performance) for the more difficult conditions of the flanker task that required the up-regulation of cognitive control to meet elevated task demands. Conclusions: These findings are consonant with the previous literature reporting a beneficial influence of aerobic fitness on cognitive control, and reveal new evidence that children without risk factors for MetS exhibit better inhibitory control and increased cognitive flexibility than do at-risk children. In addition to aerobic fitness, these risk factors may serve as important biomarkers for understanding the potential cognitive implications of MetS risk in younger generations. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
    Health psychology : official journal of the Division of Health Psychology, American Psychological Association. 08/2014;
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    ABSTRACT: Health factors such as an active lifestyle and aerobic fitness have long been linked to decreased risk of cardiovascular disease, stroke, and other adverse health outcomes. Only more recently have researchers begun to investigate the relationship between aerobic fitness and memory function. Based on recent findings in behavioral and cognitive neuroscience showing that the hippocampus might be especially sensitive to the effects of exercise and fitness, the current study assessed hippocampal-dependent relational memory and non-hippocampal-dependent item memory in young adults across a range of aerobic fitness levels. Aerobic fitness was assessed using a graded exercise test to measure oxygen consumption during maximal exercise (VO2max), and relational and item memory were assessed using behavioral and eye movement measures. Behavioral results indicated that aerobic fitness was positively correlated with relational memory performance but not item memory performance, suggesting that the beneficial effects of aerobic fitness selectively affect hippocampal function and not that of the surrounding medial temporal lobe cortex. Eye movement results further supported the specificity of this fitness effect to hippocampal function, in that aerobic fitness predicted disproportionate preferential viewing of previously studied relational associations but not of previously viewed items. Potential mechanisms underlying this pattern of results, including neurogenesis, are discussed.
    Journal of Cognitive Neuroscience 06/2014; · 4.49 Impact Factor
  • Naiman A Khan, Charles Hillman
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    ABSTRACT: Physical inactivity has been shown to increase the risk for several chronic diseases across the lifespan. However, the impact of physical activity and aerobic fitness on childhood cognitive and brain health has only recently gained attention. The purposes of this article are to: 1) highlight the recent emphasis for increasing physical activity and aerobic fitness in children's lives for cognitive and brain health; 2) present aspects of brain development and cognitive function that are susceptible to physical activity intervention; 3) review neuroimaging studies examining the cross-sectional and experimental relationships between aerobic fitness and executive control function; and 4) make recommendations for future research. Given that the human brain is not fully developed until the third decade of life, preadolescence is characterized by changes in brain structure and function underlying aspects of cognition including executive control and relational memory. Achieving adequate physical activity and maintaining aerobic fitness in childhood may be a critical guideline to follow for physical as well as cognitive and brain health.
    Pediatric exercise science 04/2014; · 1.57 Impact Factor
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    ABSTRACT: To investigate the effect of a 9-month physical activity intervention on cardiorespiratory fitness and adiposity among prepubertal children. Prepubertal children (8- to 9-year-olds, N = 220, 103 girls) were randomly assigned to a 9-month physical activity intervention or a control group. The intervention provided 70 minutes (5 days/week) of moderate to vigorous physical activity. Maximum oxygen consumption (Vo2max percentile) and dual-energy radiograph absorptiometry measured cardiorespiratory fitness and adiposity, respectively. Intention-to-treat analysis was performed to assess baseline and follow-up cardiorespiratory fitness, percentage fat mass (%FM), percentage central fat mass (%CFM), and estimated visceral adipose tissue (VAT) area. The intervention group increased in cardiorespiratory fitness (5.4th percentile; 95% confidence interval [CI], 1.8 to 8.9) and decreased in %FM (-0.7%; 95% CI, -1.1 to -0.4) and %CFM (-1.3%; 95% CI, -1.9 to -0.7). Reductions in %FM were evident for both nonoverweight (-0.62%; 95% CI, -1.07 to -0.17) and overweight or obese (-0.86%; 95% CI,-1.46 to -0.25) intervention participants. Conversely, the control group displayed no change in cardiorespiratory fitness while exhibiting increases in %FM (0.4%; 95% CI, 0.1 to 0.7), %CFM (0.6; 95% CI, 0.1 to 1.1), and VAT area (3.0 cm(2); 95% CI, 1.6 to 4.4). Nonoverweight control participants increased in %FM (0.52%; 95% CI, 0.13 to 0.91), and their overweight and obese counterparts increased in VAT (4.76 cm(2); 95% CI, 1.90 to 7.63). The physical activity intervention improved cardiorespiratory fitness, reduced %FM, and prevented accumulation of %CFM among prepubertal children with varying adiposity levels. These findings provide support for daily physical activity recommendations to prevent excess fat mass accumulation in childhood.
    PEDIATRICS 03/2014; · 4.47 Impact Factor
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    ABSTRACT: Studies in rodents and older humans have shown that the hippocampus-a brain structure critical to relational/associative memory-has remarkable plasticity as a result of lifestyle factors (eg, exercise). However, the effect of dietary intake on hippocampal-dependent memory during childhood has remained unexamined. We investigated the cross-sectional relation of dietary components characteristic of the Western diet, including saturated fatty acids (SFAs), omega-3 (n-3) fatty acids, and refined sugar, with hippocampal-dependent relational memory in prepubescent children. Participants aged 7-9 y (n = 52) reported their dietary intake by using the Youth-Adolescent Food-Frequency Questionnaire and completed memory tasks designed to assess relational (hippocampal-dependent) and item (hippocampal-independent) memory. Performance on the memory tasks was assessed with both direct (accuracy) and indirect (eye movement) measures. Partial correlations adjusted for body mass index showed a positive relation between relational memory accuracy and intake of omega-3 fatty acids and a negative relation of both relational and item memory accuracy with intake of SFAs. Potential confounding factors of age, sex, intelligence quotient, socioeconomic status, pubertal timing, and aerobic fitness (maximal oxygen volume) were not significantly related to any of the dietary intake measures. Eye movement measures of relational memory (preferential viewing to the target stimulus) showed a negative relation with intake of added sugar. SFA intake was negatively associated with both forms of memory, whereas omega-3 fatty acid intake was selectively positively associated with hippocampal-dependent relational memory. These findings are among the first to show a link between habitual dietary intake and cognitive health as pertaining to hippocampal function in childhood. FITKids and FITKids2 were registered at www.clinicaltrials.gov as NCT01334359 and NCT01619826, respectively.
    American Journal of Clinical Nutrition 02/2014; · 6.50 Impact Factor
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    ABSTRACT: The global epidemic of childhood obesity has become a major public health concern. Yet, evidence regarding the association between childhood obesity and cognitive health has remained scarce. This study examined the relationship between obesity and cognitive control using neuroelectric and behavioral measures of action monitoring in preadolescent children. Healthy weight and obese children performed compatible and incompatible stimulus-response conditions of a modified flanker task, while task performance and the error-related negativity (ERN) were assessed. Analyses revealed that obese children exhibited a longer reaction time (RT) relative to healthy weight children for the incompatible condition, whereas no such difference was observed for the compatible condition. Further, obese children had smaller ERN amplitude relative to healthy weight children with lower post-error response accuracy. In addition, healthy weight children maintained post-error response accuracy between the compatible and incompatible conditions with decreased ERN amplitude in the incompatible condition, whereas obese children exhibited lower post-error response accuracy for the incompatible relative to the compatible condition with no change in ERN amplitude between the compatibility conditions. These results suggest that childhood obesity is associated with a decreased ability to modulate the cognitive control network, involving the prefrontal cortex and anterior cingulate cortex, which supports action monitoring.
    Cerebral Cortex 11/2012; · 8.31 Impact Factor
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    ABSTRACT: To examine whether childhood obesity is associated with inhibitory control, we compared healthy weight and obese preadolescent children's task performance along with the N2 and P3 components during a Go/NoGo task. Results indicated that obese children exhibited lower response accuracy relative to healthy weight children during the NoGo task requiring greater amounts of inhibitory control, whereas no such difference was observed during the Go task. Neuroelectric data indicated that healthy weight children exhibited a more frontal distribution for the NoGo P3 relative to the Go P3, whereas obese children had similar topographic distributions between the Go P3 and NoGo P3. Further, obese children had larger NoGo N2 amplitude relative to the Go N2, whereas this difference was not observed for healthy weight children. These findings suggest that childhood obesity is negatively and selectively associated with prefrontal inhibitory control.
    Psychophysiology 08/2012; 49(10):1361-71. · 3.29 Impact Factor
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    ABSTRACT: Adiposity may be negatively associated with cognitive function in children. However, the findings remain controversial, in part due to the multifaceted nature of cognition and perhaps the lack of accurate assessment of adiposity. The aim of this study was to clarify the relation of weight status to cognition in preadolescent children using a comprehensive assessment of cognitive control, academic achievement, and measures of adiposity. Preadolescent children between 7 and 9 years (n = 126) completed Go and NoGo tasks, as well as the Wide Range Achievement Test 3rd edition (WRAT3), which measures achievement in reading, spelling, and arithmetic. In addition to body mass index (BMI), fat mass was measured using dual X-ray absorptiometry (DXA). Data were analyzed with multiple regression analysis, controlling for confounding variables. Analyses revealed that BMI and fat mass measured via DXA were negatively associated with cognitive control, as children with higher BMI and fat mass exhibited poorer performance on the NoGo task requiring extensive amounts of inhibitory control. By contrast, no relation of weight status to performance was observed for the Go task requiring smaller amounts of cognitive control. Higher BMI and fat mass were also associated with lower academic achievement scores assessed on the WRAT3. These data suggest that adiposity is negatively and selectively associated with cognitive control in preadolescent children. Given that cognitive control has been implicated in academic achievement, the present study provides an empirical basis for the negative relationship between adiposity and scholastic performance.
    Obesity 05/2012; · 3.92 Impact Factor
  • Journal of Nutrition Education and Behavior - J NUTR EDUC BEHAV. 01/2011; 43(4).
  • Journal of nutrition education and behavior 01/2009; 41(1):68-70. · 1.36 Impact Factor
  • Journal of The American Dietetic Association - J AMER DIET ASSN. 01/2008; 108(9).
  • Medicine and Science in Sports and Exercise - MED SCI SPORT EXERCISE. 01/2006; 38.

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