Dietary patterns are crucial for maintaining cognitive health among older people and can be modified through lifestyle interventions. We investigated the associations between dietary patterns, changes in these patterns over time, and cognitive function.

This cohort study utilized data from the Chinese Longitudinal Healthy Longevity Survey conducted between 2005 and 2014. The sample included 7472 participants (mean age: 81.45 ± 10.88 years). Dietary patterns were derived using cluster analysis. Cognitive function was assessed using the Mini‐Mental State Examination (MMSE). The relationships between dietary patterns/changes, MMSE scores, changes in MMSE scores, and cognitive impairment were analyzed using the generalized estimating equation method, linear regression, and logistic regression.

Cluster analysis identified three major dietary patterns: balanced diet, relatively balanced diet, and unbalanced diet. Mean MMSE scores decreased from 24.71 ± 7.24 in 2005 to 22.22 ± 9.29 in 2008, then increased to 24.10 ± 7.76 in 2014. Participants who adhered to balanced diet patterns exhibited significantly higher MMSE scores (1.56; 95% confidence interval: 1.34, 1.78) than those who followed unbalanced diet patterns. This association was particularly prominent among older individuals, women, individuals with no education, and underweight individuals. Participants with relatively balanced or balanced diets showed a significantly lower risk of cognitive impairment (adjusted odds ratio (OR) = 0.72, 95% CI: 0.65, 0.80; OR = 0.47, 95% CI: 0.42, 0.53, respectively) than those with unbalanced diets. Transitioning from an unhealthy diet to a healthy diet was associated with a smaller decline in MMSE scores and reduced risk of cognitive impairment.

These findings emphasize the importance of balanced or relatively balanced diets in preserving cognitive health in older individuals. These patterns relate to better MMSE scores and reduced cognitive impairment risk. Shifting from unhealthy to healthy diets is linked to improved MMSE scores and lower cognitive impairment risk. These results underscore the importance of dietary interventions in mitigating cognitive decline in older adults. Further research is warranted to understand the underlying mechanisms and develop targeted strategies for promoting healthy dietary habits in this population.