Dietary Fatty Acids, Cognitive Decline, and Dementia

As the therapeutic options currently available have demonstrated limited efficacy, the search for preventive strategies for cognitive decline and dementia are mandatory. A possible role of lifestyle-related factors was recently proposed for age-related changes of cognitive function, predementia syndromes, and the cognitive decline of degenerative (Alzheimer’s disease, AD) or vascular origin. An increasing body of epidemiological evidence suggested that elevated saturated fatty acids (SFA) could have negative effects on age-related cognitive decline (ARCD). Furthermore, a clear reduction of risk for cognitive decline has been found in population samples with elevated fish consumption, high intake of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), particularly n-3 PUFA. Recent findings have demonstrated that while dietary fatty acid intakes were not associated with incident mild cognitive impairment (MCI), high PUFA intake appeared to have a borderline nonsignificant trend for a protective effect against the development of MCI. These epidemiological findings on predementia syndromes, i.e., MCI or ARCD, together with recent findings from clinical trials with n-3 PUFA supplementation that showed efficacy on cognitive and depressive symptoms only in very mild AD subgroups or MCI, suggest a possible role of fatty acid intake in the maintenance of adequate cognitive functioning and possibly in the prevention and management of cognitive decline and dementia.