Recent advances in nutrition have uncovered a number of nutrients that play an important role in brain function. Of these the most researched and most promising are the marine fatty acids found in cold water fish. Fish contains two fatty acids that may be important in proper brain function. One is a 22 carbon compound called docosahexanoic acid (DHA, C22:6 (n-3)) and the other is a 20 carbon compound called eicosapentanoic acid (C20:5 (n-3)). Both of these compounds are metabolites of the vitamin-like fatty acid alpha-linolenic acid (ALA, C:18 (n-3)), which is essential to human health. Evidence suggest that DHA and EPA are necessary for neuronal communication and eicosanoid production. In the early years of life and through adolescence, deficiency can result in problems with learning and low IQ. In later life, deficiency is associated with neurodegeneration and elevated risk for Alzheimer’s disease.
Research published in the Journal of Nutrition in 20101 investigated the association between plasma phospholipid levels of ALA, EPA and DHA and the major dimensions of cognitive function in 280 healthy individuals between 35 and 54 years of age. The cognitive testing involved non-verbal reasoning and mental flexibility, attention and concentration, general memory, working memory, and verbal knowledge and processing. The results demonstrated that of the fatty acids, phospholipids levels of DHA were most strongly related to cognitive function. In particular, phospholipids levels of DHA were associated with better results on the tests for non-verbal reasoning and mental flexibility as well as working memory. Phospholipid levels of EPA were not as strongly associated with cognitive performance, as there was only an association between EPA and a sub-set of working memory test scores. Levels of ALA did not show any association to cognitive performance.
Fish is often referred to as brain food in tradition and it appears that there is some merit to this myth. The n-3 group of fatty acids in marine oils are emerging as important components of healthy brain function in humans. These results support previous findings from studies involving postnatal and elderly subjects, that suggest phospholipids levels of fatty acids from fish oils are associated with improved brain development or function. In addition, the results also support other studies that have found that consumption of the parent n-3 fatty acid ALA might not be as beneficial to health consumption of the fish derived metabolites EPA or DHA. This may relate to the fact that ALA is reliant on a series of desaturase and elongase enzyme (which may not be fully functional in some individuals) in order to allow eicosanoid production, whereas DHA and EPA are not.
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