Recent prospective studies provided evidence that higher adherence to a Mediterranean-type diet could be associated with slower
cognitive decline, reduced risk of progression from
mild cognitive impairment to
Alzheimer's disease (AD), reduced risk of AD, and decreased mortality in AD patients. Furthermore, the
Mediterranean diet (MeDi) combines several foods, micro- and macronutrients already separately proposed as potential protective factors against
dementia and predementia syndromes. At present, epidemiological evidence suggests a possible association between fish consumption,
monounsaturated fatty acids, and
polyunsaturated fatty acids (PUFA) (particularly,
n-3 PUFA), and reduced risk of
cognitive decline and
dementia. Light to moderate alcohol use may be associated with a reduced risk of incident
dementia and AD, while for
vascular dementia,
cognitive decline, and predementia syndromes, the current evidence is only suggestive of a protective effect. Finally, the limited epidemiological evidence available on fruit and vegetable consumption and cognition generally support a protective role of these macronutrients against
cognitive decline,
dementia, and AD. We reviewed evidence on the possible mechanisms underlying the suggested protective role of MeDi against age-related changes in cognitive function, predementia syndromes, and
dementia, examining the possible role of macronutrients and food nutrients of the MeDi and their nutraceutical properties in modulating the risk of
cognitive decline. Although vascular variables are likely to be in the causal pathway between MeDi and
dementia syndromes and should be considered as possible mediators, other nonvascular biological mechanisms (i.e., metabolic, oxidative, and inflammatory) may be invoked to explain the complex epidemiological association between MeDi and
cognitive decline.