Fatty acid intake and the risk of dementia and cognitive decline: a review of clinical and epidemiological studies.

Dietary intake of fatty acids may be related to dementia and cognitive function through a number of plausible mechanisms, such as atherosclerosis and thrombosis, inflammation, via an effect on brain development and membrane functioning, or via accumulation of beta-amyloid. This review gives an overview of the few studies that have investigated the relationship between fatty acid intake (including the fatty acids from fish) and cognitive function or dementia and summarises the results from two Dutch population-based prospective studies: the Zutphen Elderly Study (n=476) and the Rotterdam Study (n=5,386). Additionally, limitations on dietary intake studies are discussed and possible mechanisms behind the investigated associations. Data from the Rotterdam Study showed that high intakes of the following nutrients were associated with an increased risk of dementia after adjustment for confounders: total fat (RR=2.4 (95%CI: 1.1-5.2)), saturated fat (RR=1.9 (95%CI: 0.9-4.0)), and cholesterol (RR=1.7 (95%CI: 0.9-3.2)). A high fish consumption, an important source of n-3 PUFAs, reduced the risk of dementia (RR=0.4 (95%CI: 0.2-0.9)). In the Zutphen Elderly Study a high linoleic acid intake was associated with cognitive impairment (OR=1.8 (95%CI: 1.0-3.0)). A high fish consumption tended to be inversely associated with cognitive impairment and decline (RR=0.5, 95%CI: 0.2-1.2). Since diet is a risk factor that is suitable for intervention these results are hopeful and potentially very important.