Association of whole grain intake with cognitive function among middle-aged and older adults in China

Background: Whole grains, rich in dietary fiber, vitamins, minerals, and phytochemicals, are beneficial to human health. However, evidence regarding the relationship between whole grain intake and cognitive function remains limited. Objective: This cross-sectional study aimed to investigate the association between whole grain intake and global cognition, specific cognitive domains, and the risk of mild cognitive impairment (MCI) among middle-aged and older adults in China. Methods: This study included 5020 participants with a mean age of 63.76 years from the Chinese Square Dance Cohort. Dietary intake was assessed using a 64-item semi-quantitative food frequency questionnaire (FFQ), and daily whole grain intake was calculated. Global cognition was evaluated through a composite z-score based on the Auditory Verbal Learning Test (AVLT), Digit Symbol Substitution Test (DSST), Verbal Fluency Test (VFT), and Trail Making Test B (TMT-B). MCI was diagnosed according to Petersen's criteria. The relationship between whole grain intake and cognitive scores was analyzed using multiple linear regression, with results expressed as β coefficients and 95% confidence intervals (CIs). The association between whole grain intake and MCI was assessed using logistic regression models, with results expressed as odds ratios (ORs) and 95% CIs. Results: In this study, a total of 622 participants were diagnosed with MCI. After adjusting for covariates, compared to the lowest quartile of whole grain intake, the highest quartile was associated with higher composite z-scores (β_Q4 = 0.13, 95% CI: 0.09, 0.18), AVLT scores (β_Q4 = 0.16, 95% CI: 0.10, 0.23), VFT scores (β_Q4 = 0.18, 95% CI: 0.11, 0.26), and DSST scores (β_Q4 = 0.07, 95% CI: 0.01, 0.12), as well as lower TMT-B completion time (β_Q4 = -0.12, 95% CI: -0.20, -0.05). In addition, each 25 g d^-1 increment in whole grain intake was associated with 18% lower odds of MCI (OR = 0.82, 95% CI: 0.74, 0.91; P for trend < 0.001). Conclusions: Higher whole grain intake was associated with better cognitive function and lower risk of MCI among middle-aged and older adults in China, suggesting potential benefits for cognitive health. Future longitudinal and interventional studies are needed to confirm this association and establish causality.