Association between glycemic load and cognitive function in community-dwelling older adults: Results from the Brain in Motion study.

Background: Impaired glucose tolerance is a risk factor for non-age-related cognitive decline and is also associated with measures of physical activity (PA) and cardiorespiratory fitness (CRF). A low glycemic load (GL) diet can aid in the management of blood glucose levels, but little is known about its effect on cognition with poor glucoregulation.

Objective: We assessed the relation between GL and cognitive function by glucoregulation and possible mediatory effects by CRF and PA in older adults from the Brain in Motion Study.

Design: A cross-sectional analysis of 194 cognitively healthy adults aged ≥55 years (mean = 65.7, SD = 6.1) was conducted. GL was assessed using a quantitative food frequency questionnaire, and glucoregulation was characterized on the HOMA-IR index. Subjects also completed a cognitive assessment, CRF testing, a validated self-reported PA questionnaire, and a blood draw. Multiple linear regression models adjusted for significant covariates were used to evaluate the relation between GL and cognition, and mediation by CRF and PA was also assessed.

Results: GL was inversely associated with global cognition (β = -0.014; 95% CI -0.024, -0.004) and figural memory (β = -0.035; 95% CI -0.052, -0.018) in subjects with poor glucoregulation. Neither CRF nor PA mediated these relations. In subjects with good glucoregulation, no association was found between GL and cognitive function (p > 0.05).

Conclusions: A low GL diet is associated with better cognitive function in older adults with poor glucoregulation. This study provides supportive evidence for the role of GL in maintaining better cognitive function during the aging process.