Higher adherence to MedDiet and DASH associated with better executive function in aging populationsMediterranean and DASH diets linked to better brain health

This meta-analysis synthesized data from 8 longitudinal cohorts involving a total of 17,368 individuals from aging populations in Europe and the United States. The study aimed to evaluate the relationship between adherence to various dietary patterns and cognitive outcomes, specifically focusing on global cognition and executive function. The dietary patterns analyzed included the Healthy Eating Index-2020 (AHEI-2020), AHEI-2010, EAT-Lancet, Mediterranean Diet (MedDiet), DASH, and MIND. Additionally, the study examined the impact of specific food groups, namely red meat and processed meat, on cognitive health.

The primary outcomes measured were global cognition, assessed via the Mini-Mental State Examination, and executive function, assessed via the Trail Making Test Part B. The analysis evaluated how adherence to the various dietary patterns influenced these outcomes over time. Furthermore, the study looked at the specific impact of red and processed meat consumption on executive function trajectories and outcomes.

Regarding global cognition, the analysis found that higher adherence to the continuous MedDiet was associated with better global cognition. However, the study did not report specific effect sizes, absolute numbers, or p-values for this finding. For executive function, the results indicated that higher adherence to both the continuous MedDiet and the DASH diet was associated with better executive function. Similarly, no specific statistical measures were provided for these associations.

In terms of specific food groups, the results showed that greater consumption of red and processed meat was associated with poorer executive function. Regarding longitudinal trajectories, the analysis found that only the MIND diet (which was assessed in 3 US cohorts) was associated with more favorable executive function trajectories. The study noted that these findings are based on observational data, and therefore, the results indicate associations rather than direct causation.

Safety and tolerability data were not reported in the study, as is common in observational meta-analyses of dietary patterns. The study did not report any specific adverse events, serious adverse events, or discontinuation rates. The focus remained on the correlation between dietary habits and cognitive performance in an aging population.

These findings contribute to the understanding of how dietary habits may influence cognitive health in older adults. While the associations with MedDiet and DASH are positive, the results are tempered by significant methodological limitations. The study noted substantial between-study heterogeneity for the DASH, MIND, and AHEI-2010 patterns. Furthermore, longitudinal findings were described as limited and inconsistent, and there were no consistent longitudinal associations found for specific food groups.

Clinically, these results suggest that while certain dietary patterns like MedDiet and DASH are associated with better executive function and global cognition, the associations may be modest and are highly sensitive to measurement constraints. The findings highlight a need for more sensitive cognitive phenotyping and prospectively harmonized study designs in future research. Currently, these results should be interpreted as observational evidence of association rather than definitive proof of a causal link between specific diets and cognitive preservation.

Several questions remain unanswered due to the limitations of the current data. Specifically, the lack of consistent longitudinal findings for food groups and the high heterogeneity among different dietary indices suggest that the impact of specific nutrients or combinations of foods is not yet clearly defined. Future research must address these inconsistencies to provide clearer guidance on which specific dietary components most effectively support cognitive health in aging populations.