Mediterranean diet and cognitive decline: what role for omega-3 polyunsaturated fatty acids?

The Mediterranean diet is characterized by a high consumption of fruits, vegetables, legumes, cereals, and olive oil as the main source of added fat, a moderate consumption of fish and wine, and a low consumption of meat and dairy products as a source of saturated fat. Several epidemiological studies have shown that higher adherence to a Mediterranean diet was associated with slower cognitive decline in older persons. This protective effect might be mediated by omega-3 poly-unsaturated fatty acids (n-3 PUFA). We investigated this hypothesis in 1050 participants in the 3City study from Bordeaux. After multivariable adjustment including apolipoprotein E (ApoE) genotype, plasma docosahexaenoic acid and total n-3 PUFA were positively associated with a score of adherence to a Mediterranean diet. Plasma eicosapentaenoic acid was positively associated with adherence only in ApoE4 non-carriers. These data suggest that the protective effect of the Mediterranean diet on cognitive functions might be partly mediated by higher plasma n-3 PUFA.