Effects of N-3 Polyunsaturated Fatty Acids on Dementia.

Key Findings

This paper provides a review on the relationship of serum n-3 PUFAs with risk of dementia. Serum ALA, EPA, and DHA were measured in 315 cases of incident disabling dementia. Serum ALA level was inversely associated with risk of disabling dementia. Associations of EPA and DHA with disabling dementia were not statistically significant. Recent studies have also demonstrated a significant negative association of ALA with dementia. In the analyses of observational studies, three studies reported a significant association between ALA and dementia. In the analyses of intervention studies, n-3 PUFAs have been reported to improve dementia in three studies. EPA + DHA supplementation was beneficially associated with dementia in three studies; however, four studies reported the negligible effects of EPA + DHA for dementia.  The review concluded that patients with mild memory and/or cognitive impairment can be treated by a long-term and higher intake of n-3 PUFA.

ABSTRACT

N-3 polyunsaturated fatty acids (PUFAs) including α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti-inflammatory effects and neuronal protective functions and may benefit prevention of dementia; however, the epidemiological evidence is very limited. Therefore, the literature about the association between n-3 PUFA and dementia was searched, by using Pubmed. In the analyses of observational studies, n-3 PUFA has been reported to be beneficially associated with dementia in 17 studies; however, the beneficial association between n-3 PUFA and dementia was denied by three studies. In the analyses of intervention studies, n-3 PUFA supplementation was beneficially associated with dementia in eight studies; however, five studies reported the negligible effect of n-3 PUFA for dementia. N-3 PUFA may improve Alzheimer’s disease by increasing clearance of amyloid-β peptide, neurotrophic and neuroprotective factors, and by anti-inflammatory effects. In conclusion, patients with mild memory and/or cognitive impairment can be treated by a long-term and higher intake of n-3 PUFA.