[Note: DHA is an omega-3 fatty acid that is plentiful in fish oil. It is a type of polyunsaturated fatty acid or "PUFA."]
Existing evidence links greater dietary intake of fish and (omega-3) PUFA [polyunsaturated fatty acid] to better early brain development and lowered risk of cognitive disorders in late life. The mechanisms for these associations remain unclear and may be related to specific (omega-3) fatty acids and may concern cognitive function generally rather than only early brain development and age-related cognitive dysfunction.
In this investigation, we tested potential associations between (omega-3) fatty acids in serum phospholipids and major dimensions of cognitive functioning in mid-life adults.
Participants were 280 community volunteers between 35 and 54 years of age, free of major neuropsychiatric disorders, and not taking fish oil supplements.
Dietary biomarkers were alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenonic acid (DHA) in serum phospholipids measured using GC.
Five major dimensions of cognitive functioning were assessed with a 75-min battery of neuropsychological tests. In covariate adjusted regression models, higher DHA (mol %) was related to better performance on tests of nonverbal reasoning and mental flexibility, working memory, and vocabulary (P = 0.05). These associations were generally linear. [Increasing DHA levels, better performance.]
Associations between DHA and nonverbal reasoning and working memory persisted with additional adjustment for participant education and vocabulary scores (P = 0.05).
Neither EPA nor ALA was notably related to any of the 5 tested dimensions of cognitive performance. Among the 3 key (omega-3) PUFA, only DHA is associated with major aspects of cognitive performance in nonpatient adults younger than 55 y old.
These findings suggest that DHA is related to brain health throughout the lifespan and may have implications for clinical trials of neuropsychiatric disorders.
Source: Journal of Nutrition, Feb 24, 2010. PMID: 20181791, Muldoon MF, Ryan CM, Sheu L, Yao JK, Conklin SM, Manuck SB. Center for Clinical Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.