Mediterranean diet and risk for dementia and cognitive decline in a Mediterranean population

Current evidence suggests that nutrition in general and specific dietary patterns in particular, such as the Mediterranean type diet (MeDi), can be employed as potential preventive strategies against the development of dementia and cognitive decline. However, longitudinal data exploring the applicability of these findings in populations of Mediterranean origin are limited. The aim of the present study was to explore the potential relationships of MeDi adherence with dementia incidence rates and cognitive change over time in a traditional Mediterranean population, characterized by a lifelong exposure to Mediterranean eating habits and lifestyle.

The sample consisted of 1046 non-demented individuals over the age of 64 (mean age = 73.1; SD = 5.0), with available baseline dietary information and longitudinal follow-up. Diagnosis of dementia was made by a full clinical and neuropsychological evaluation, while cognitive performance was assessed according to five cognitive domains (memory, language, attention-speed, executive functioning, visuospatial perception) and a global cognitive score. Adherence to MeDi was evaluated by an a priori score (range 0-55), derived from a detailed food frequency questionnaire.

A total of 62 incident dementia cases occurred during a mean (SD) of 3.1 (0.9) years of follow-up. Individuals in the highest MeDi quartile (highest adherence to MeDi) had a 72% lower risk for development of dementia, compared to those in the lowest one (p = 0.013). In addition, analysis of cognitive performance as a function of MeDi score revealed that the biennial cognitive benefit of a 10-unit increase in MeDi score offsets the cognitive decline associated with 1 year of cognitive aging.

In the present study, higher adherence to MeDi was associated with a reduced risk for dementia and cognitive decline in a traditional Mediterranean population.