Epidemiological and fundamental research carried out in recent years has highlighted the role played by omega-3 fatty acids in the process of cognitive decline that accompanies advancing age and Alzheimer's disease. In addition, it has been recognized for some years, following several convergent studies on the prevention of cognitive decline, that nutrition, physical exercise, cognitive training and social activities play a significant role in the maintenance of cognitive faculties. At present, there are a number of epidemiological arguments in favour of a protective role of each of these factors taken in isolation. It can be postulated that a multi-domain intervention may potentiate the protective role of omega-3 fatty acids.