White matter integrity as a mediator in the relationship between dietary nutrients and cognition in the elderly

Abstract

Objective We examined the association of nutrient intake with microstructural white matter integrity, and the role of white matter integrity in the association between nutrient consumption and cognition. Methods This cross-sectional analysis included 239 elderly (≥65 years) participants of a multiethnic cohort. White matter integrity was measured with fractional anisotropy (FA) from diffusion tensor magnetic resonance imaging. Nutrient patterns were derived from principal component analysis based on energy-adjusted intake of 24 selected nutrients. Generalized linear models were used to assess the association between nutrient patterns and mean FA of 26 white matter tracts. Mediation analysis was used to determine if FA mediates the nutrient-cognition relationship. All models were adjusted for age at time of scan, gender, ethnicity, education, caloric intake, and Apolipoprotein genotype. Results Among the identified 6 nutrient patterns, one (nutrient pattern-6, characterized by high intakes of Ω-3 and Ω-6 poly-unsaturated fatty acids and vitamin E) was positively associated with FA. Those with the highest tertile of nutrient pattern-6 score had a mean of 0.01 (p=0.01) higher FA value than those with the lowest tertile, similar to the effect of a ten-year decrease in age (b for age=−0.001, p=0.01). FA mediated the relationship between nutrient pattern-6 and memory, language, visuospatial and speed/executive function, and mean cognitive scores. Interpretation Our study suggests that older adults consuming more poly-unsaturated fatty acids and vitamin E rich foods had better white matter integrity, and that maintaining white matter microstructural integrity might be a mechanism for the beneficial role of diet on cognition.

Parahippocampal Cortex Mediates the Relationship between Lutein and Crystallized Intelligence in Healthy, Older Adults

“…Rather than claiming the parahippocampal cortex as the sole mediator of the relationship between lutein and crystallized intelligence, this study suggests that preserving structural integrity of the parahippocampal cortex is one mechanism through which lutein contributes to the preservation of cognitive function. These findings add to a growing line of evidence which suggests that particular nutrients may slow or prevent aspects of age-related cognitive decline by targeting specific features of brain aging (Bowman et al, 2012; Zamroziewicz et al, 2015; Gu et al, 2016). In the case of lutein, future studies are needed to assess whether lutein is uniquely protective of crystallized intelligence and temporal cortex structure, or whether other carotenoids contribute neuroprotective effects as well.…”

“…Accumulating evidence indicates that particular nutrients may slow or prevent aspects of age-related cognitive decline by targeting specific features of brain aging. Studies that couple neuroimaging techniques with neuropsychological testing provide insight into mechanisms of action through which particular nutrients might influence specific aspects of age-related cognitive decline (Bowman et al, 2012; Zamroziewicz et al, 2015; Boespflug et al, 2016; Gu et al, 2016). While some nutrients may be effective at preventing late-life changes in the brain, other nutritional factors may accumulate across the lifespan and therefore confer neuroprotection in the aging brain (Söderberg et al, 1990; Coyle and Puttfarcken, 1993).…”

Circulating inflammatory biomarkers in relation to brain structural measurements in a non-demented elderly population

“…Twenty-six ROIs in left and right hemispheres, and midline structures, were considered for analysis. A mean FA value of the 26 tracts was calculated and used in the analysis(61). FA ranges from 0 to 1, with higher values indicating greater orientation of diffusion and preserved microstructure.…”

“…We then examined univariate F tests for individual ROIs. A similar analysis was conducted for 12 thickness ROIs that have been shown to reflect AD-associated neurodegeneration (63, 64) (see supplementary data), and for 26 white matter tracts (61). Because individual ROI analyses were guided by the MANOVA results, and were essentially exploratory, no correction for multiple comparisons has been performed.…”

Novel Translational Research Methodology and the Prospect to a Better Understanding of Neurodegenerative Disease

“…To this effect, the state-of-the-art implementation of clinical research methodology and the establishment of informative biomarkers will play a decisive role. Adam Brickman, from Columbia University, is an expert in this emerging research field, and recent work of him and his team has substantially contributed to better understand the role of white matter pathology in AD [25, 26] and the interplay between vascular disease and AD pathology [27, 28]. Considering the complexity of the clinical phenotype observable during the progression of neurodegenerative syndromes, interactive effects between genetic determination and environmental factors might be accountable [29, 30].…”