Cortical Gray Matter Volume Associations with Dietary Fiber and Calorie Density: A Pilot Study

Alzheimer's disease and related dementia are associated with significant societal costs and economic burdens and have been associated with decreases in cortical gray matter volume. This pilot cross-sectional study investigates the relationship between total fiber concentration in diet, total calorie density per diet, and regional GMV in a cohort of 190 patients aged 20 to 79 years, utilizing data from the 2015 National Health Interview Survey Supplement and T1-weighted magnetic resonance imaging (MRI) collected at the McCausland Center for Brain Imaging. Gray matter volumes were quantified using the CAT12 voxel-based morphometry toolbox and statistical correlations between GMV and dietary measures were assessed using Spearman's rank order correlation coefficient. Our exploratory analysis revealed a significant positive correlation between dietary fiber consumption and GMV in 16 different areas, including the right Hippocampus (r (190) = 0.196, p = 0.003) and left Hippocampus (r (190) = 0.135, p = 0.032), when controlling for age and race of participants. Our analyses revealed significantly negative correlations between total calorie density per diet and localized GMV in 3 different brain areas, including the right Precentral Gyrus (r (190) = -0.15, p = 0.039) and right Thalamic Pulvinar (r (190) = -0.155, p = 0.033), when controlling for participant race. Together, our initial findings suggest that dietary fiber and calorie density are associated with GMV even after controlling for relevant demographic variables. If replicated, these findings could have important implications for dietary advice given to individuals at risk for developing MCI or more serious forms of dementia.