[Does Omega-3 supplementation after the age of 65 influence cognitive function? Results of a systematic review]

The percentage of the older population is progressively increasing as are diseases associated with aging such as cognitive decline (CD) and dementia. Observational epidemiological studies suggest that diets rich in omega 3 polyunsaturated fatty acids (w3-PUFA) might reduce the risk of CD and dementia. The main objective was to assess whether there is sufficient scientific evidence about the relationship between w3-PUFA supplementation in patients aged 65 or older and cognitive performance.

We used the Pubmed data base to search for articles related to w3-PUFA and CD or dementia. Initially we identified 582 articles, after applying the eligibility criterion we included six studies in this systematic review.

The studies included were heterogeneous regarding population, measurement of exposure and outcome. Therefore, it was not possible to conduct a quantitative analysis. Two studies found that w3-PUFA supplementation decreased the risk of Alzheimer and improved cognitive performance. Two studies found an improvement in only one of the domains of cognitive performance (visual analogical classification and verbal fluency) and another two did not find any evidence of protection.

We found few studies to support or refute the evidence that w3-PUFA supplementation in patients aged 65 or older improves cognitive performance or prevents dementia.