Mediterranean diet is a term used to describe the diet traditionally followed in Crete, South Italy and other Mediterranean countries. The traditional Mediterranean diet is characterized by high consumption of vegetables, fruits and legumes. It also includes moderate amounts of dairy products (principally cheese and yogurt), low to moderate amounts of seafood and poultry, and red meat in low amounts. Olive oil is the main type of added fat and wine is consumed modestly, normally with meals.

The Mediterranean diet has been consistently linked with long life expectancy and lower prevalence of several chronic diseases (cardiovascular disease, cancer, type 2 diabetes, metabolic syndrome). Many observational studies have explored the potential association between adherence to the Mediterranean diet and cognitive decline. For that purpose, this review evaluates existing evidence on the effect of the Mediterranean diet as a pattern on cognitive function and risk of dementia and explores potential interactions between this dietary pattern and other behaviors, implying the potential synergistic effect of a lifestyle pattern.

Effect of the Mediterranean diet on cognition and dementia

Many studies investigated the hypothesis of a potential relationship between adherence to the Mediterranean diet and Alzheimer Disease and/or cognitive decline. Among the foods and nutrients abundant in the Mediterranean Diet, olive oil (through monounsaturated fatty acids and tyrosol, caffeic acid and other phenolic compounds), fish (and n-3 polyunsaturated fatty acids), wine (through alcohol, and phenolic compounds like resveratrol) and fruits and vegetables abundant in flavonoids and vitamins like C and E, have been associated with lower inflammatory and oxidative load and have been inversely associated with cardio metabolic risk factors, cognitive decline and dementia¹. However, other studies failed to detect an association between a score related to adherence to the Mediterranean diet and prospectively assessed measures of cognitive decline.

Several explanations have been given for this conflicting aspect. Although diet may share important associations with cognitive health, these associations are complex and could vary across geographic, cultural, or socio demographic contexts. Mediating factors, geneenvironment interactions, or environmental interactions may be present and influence outcomes in different population groups. Thus, lifestyle behaviors seem to be an important component of the Mediterranean way of living.

Moving from the Mediterranean diet to a Mediterranean lifestyle

In the early Mediterranean diet pyramid², lifestyle behaviors have not been strongly emphasized as important components of the Mediterranean way of living: apart from physical activity, lifestyle factors that have been mentioned as being of particular interest are social support, sharing food, having lengthy meals and post-lunch siestas. Thus, there are no studies considering other diet-related habits, including meal patterns, structure and commensal rituals as fullfledged elements of the Mediterranean diet.

For that purpose, the Mediterranean Diet Foundation launched the new Mediterranean diet concept in 2011³. It was again depicted in the form of a pyramid, but, interestingly, it refers more to a lifestyle pattern. The new model takes into account qualitative and quantitative elements for the selection of foods in which social and cultural elements characteristic of the Mediterranean way of life are incorporated. This new model underlines the conviviality aspect of eating as it contributes to strengthening socialization, communication and social support and adequate sleep and resting during daytime as basic complements to the dietary pattern.

Effect of the New Mediterranean diet on dementia

This revised clustering of patterns related to food intake, physical activity and social life has not been evaluated in relation to dementia. However, there is evidence indicating that these factors individually are important to cognitive function and decline; they may inter-correlate or act synergistically.

Indeed, social interaction such as mealtime conversations, group leisure activities or other forms of social engagement has been studied in relation to the prevalence, incidence of a dementia or in the context of non-pharmacological treatments, mainly along with physical activity.

According to many studies^2,4, socialization has been related to better cognitive performance and social interactions have been found to maintain and reaffirm individual and group identities in families living with dementia⁵. It has also been hypothesized that increased social interaction may benefit Alzheimer’s patients by minimizing the sense of loneliness, isolation, stress, and, also vascular factors that contribute to cognitive decline. It can also improve patients’ sense of self-worth⁶. This new approach may help understand in more depth the role of the Mediterranean diet and to develop even more comprehensive intervention strategies with a promising potential regarding cognitive health.

Based on: Yannakoulia M, Kontogianni M, Scarmeas N. 2015 Mar. Cognitive health and Mediterranean Diet: Just diet or lifestyle pattern? Ageing Res Rev.