Understanding the ‘traditional’ Mediterranean cuisine: relationship to cognitive health and advances in measurement of adherence

Abstract

The Mediterranean diet has been associated with reduced chronic disease risk. Recent research is focussing on cognitive function as dementia is a global health priority. Varied Mediterranean diet interventions and adherence tools have impeded comparisons across trials. No tool has been specifically developed for, nor validated within, cohorts at increased dementia risk. The aims of this thesis were to improve understanding of the ‘traditional’ Mediterranean cuisine; systematically review the effect of a Mediterranean diet on cognition and brain morphology/function within clinical trials; develop a new index tool to assess adherence to the ‘traditional’ dietary pattern and aspects of cuisine; and test reliability and validity of this tool for online and in-person use among older Australians, including those with mild cognitive impairment. This thesis has identified additional culinary aspects of the ‘traditional’ cuisine, which were previously poorly examined. The systematic review found no overall cognitive benefits for a Mediterranean diet across included trials but the interventions variably reflected a ‘traditional’ diet. In the best trial, cognitive decline was reduced over four years compared to a lower fat diet. The Mediterranean Diet and Culinary Index (MediCul) (scored from 0 to 100) was developed using elements and cut-off points based on the ‘traditional’ cuisine. This survey tool, taking 20 minutes to complete, was tested within two cohorts and found to have very good reliability using the intra-class correlation coefficient (ICC) (ICC=0.86, 95% CI: 0.789, 0.910 and ICC=0.93, 95% CI: 0.884, 0.954, respectively, p<0.0001). Validity was moderate with the tool overreporting the MediCul score by 6% compared to a food record. Promotion of lifestyle interventions to slow progression of cognitive decline in at-risk groups is critical. Availability of validated tools such as MediCul may advance understanding of the role of diet in healthy brain ageing.