Mediterranean-based Diets and their Association with Cognitive Functioning in Dutch Community-Dwelling Older Adults

Abstract

Background: Lifestyle has become an important focus of brain health, due to its potential to delay cognitive decline. Previously, nutritional patterns such as the Mediterranean diet and the MIND diet have been associated with a reduced risk of cognitive impairment. However, there are still conflicting results regarding the effect sizes of these diets, warranting further research. Therefore, the aim of the current project was to analyze the association between adherence to the Mediterranean diet, measured by the MEDI-LITE score (Mediterranean Literature score), and cognitive function in the NU-AGE Wageningen cohort.

Methods: Food records and cognitive scores were obtained from the NU-AGE Wageningen cohort, which was a one-year randomized dietary intervention study in healthy older adults (65-79 years). The MEDI-LITE score (ranging from 0-18) was calculated from seven-day food records and was analyzed as total score, as well as in separate food categories. Four cognitive domains were created from composite Z-scores of individual neuropsychological test battery scores. Linear regression was used to model the relationship between MEDI-LITE scores and cognitive scores, and p-values were adjusted for multiple testing.

Results: In total, 248 out of 252 participants had complete data available at baseline. The MEDI-LITE total score was negatively associated with episodic memory [β -0.05 (99% CI -0.11, -0.01), p=0.022], but this trend did not remain significant after adjustment. In the separate food categories, non-significant negative trends were observed between fish and executive functioning [β -0.29 (99% CI -0.62, -0.03), p=0.026] and episodic memory [β -0.23 (99% CI -0.52, -0.06), p=0.021]. Cereal intake showed a non-significant negative trend with episodic memory [β -0.33 (99% CI -0.73, -0.07), p=0.033].

Discussion & Conclusion: We did not find a significant association between adherence to the Mediterranean diet and cognition scores in the NU-AGE Wageningen cohort. Although some other studies have reported similar non-significant associations between the Mediterranean diet and cognition, there is ample evidence that this diet improves cognitive function and delays cognitive impairment. The non-significant findings in this report could have been the result of selection bias, reverse causation, the unvalidated analysis of separate food categories of the MEDI-LITE score or the lack of distinction between types of foods (e.g. refined or non-refined cereals). Future randomized trials with generalized scores and guidelines are necessary to confirm the association between the Mediterranean diet and cognitive functioning in older adults.