Available online 2 March 2023

Body fat % is negatively associated with total and regional gray matter volume

High body fat % is associated with lower regional neural integrity

Handgrip correlates to increased neural integrity and decreased blood inflammation

Muscle mass and physical performance are correlated with a loss in neural integrity

Stronger older adults with a healthy body fat % have in general better brain health

Obesity and sarcopenia are associated with cognitive impairments at older age. Current research suggests that blood biomarkers may mediate this body-brain crosstalk, altering neurometabolism and brain structure eventually resulting in cognitive performance changes. Seventy-four older adults (60-85 years old) underwent bio-impedance body composition analysis, handgrip strength measurements, 8-Foot Up-and-Go (8UG) test, Montreal Cognitive Assessment (MoCA), blood analysis of interleukin-6 (IL-6), kynurenine, and insulin-like growth factor-1 (IGF-1), as well as brain magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS), estimating neurodegeneration and neuroinflammation. Normal fat% or overweight was associated with larger total gray matter volume compared to underweight or obesity in older adults and obesity was associated with higher N-acetylaspartate/Creatine levels in the sensorimotor and dorsolateral prefrontal cortex. Muscle strength, not muscle mass/physical performance, corresponded to lower kynurenine and higher N-acetylaspartate/Creatine levels in the dorsal posterior cingulate and dorsolateral prefrontal cortex. The inflammatory and neurotrophic blood biomarkers did not significantly mediate these body-brain associations. This study used a multimodal approach to comprehensively assess the proposed mechanism of body-brain crosstalk.

proton magnetic resonance spectroscopy

dorsolateral prefrontal cortex

dorsal posterior cingulate cortex

enzyme-linked immunosorbent assay

European Working Group on Sarcopenia in Older People

full width at half maximum

glutamate-glutamine complex

intraclass correlation coefficient

insulin-like growth factor-1

linear combination of model spectra

Montreal Cognitive Assessment

magnetization prepared gradient echo

medial temporal cortex

Point RESolved Spectroscopy

primary sensorimotor cortex

skeletal muscle mass index

total N-acetyl aspartate

tumor necrosis factor-α

Body composition

cognition

aging

physical fitness

neuroinflammation

neurotrophic factor

© 2023 The Author(s). Published by Elsevier Inc.