Increased blood levels of DHA were associated with improved nonverbal reasoning and working memory in people between 35 and 54, but intakes of other omega-3 fatty acids ALA (alpha-linolenic acid) and EPA (eicosapentaenoic acid) were not, according to findings published in the Journal of Nutrition.
“These findings suggest that DHA is related to brain health throughout the lifespan and may have implications for clinical trials of neuropsychiatric disorders,” wrote the researchers, led by Matthew Muldoon from the University of Pittsburgh.
The potential brain boosting benefits of omega-3 have been reported by numerous studies, most recently at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD 2009) in Vienna. Scientists reported in the Austrian capital that daily supplements with the omega-3 fatty acid docosahexaenoic acid (DHA) may improve both memory function and heart health in healthy older adults. The study presented at the Alzheimer's conference was funded by Martek Biosciences.
Muldoon and his co-workers analysed data from 280 community-dwelling people aged between 35 and 54. The participants were not taking fish oil or omega-3 supplements and were free of major neuropsychiatric disorders.
Blood levels of ALA, EPA, and DHA were correlated with five major dimensions of cognitive functioning of neuropsychological tests. Average levels of the fatty acids were 0.16, 0.49, and 1.52, respectively, as a percentage of the total phospholipid fatty acids.
“Higher DHA was related to better performance on tests of nonverbal reasoning and mental flexibility, working memory, and vocabulary,” said the researchers. Furthermore, increasing levels of DHA were associated with improved mental function in a “generally linear” relationship, they said.
On the other hand EPA and ALA were not associated with cognitive performance.
“Among the 3 key omega-3 PUFA, only DHA is associated with major aspects of cognitive performance in non-patient adults younger than 55 y old,” concluded Muldoon and his co-workers.
Plenty more science to do
“The findings from these analyses derive from cross-sectional data and, therefore, cannot establish that any association between the omega-3 fatty acids on cognitive performance is causal,” stated the researchers.
“While this and prior observational studies of omega-3 fatty acids and cognitive function have generally found associations that withstand adjustment for obvious confounding factors, additional intervention-based experiments and randomized clinical trials in both healthy and clinical samples are warranted.
“Taken together, research to date suggests that specifically, DHA may favourably affect cognitive performance and may do so throughout the life course,” they concluded.
Source: Journal of Nutrition
Publshed online ahead of print, doi:10.3945/jn.109.119578
“Serum Phospholipid Docosahexaenonic Acid Is Associated with Cognitive Functioning during Middle Adulthood”
Authors: M.F. Muldoon, C.M. Ryan, L. Sheu, J.K. Yao, S.M. Conklin, S.B. Manuck