A new study published in The Journal of Nutrition suggests that positive associations between omega-3 polyunsaturated fatty acids and better cognitive function may vary according to other dietary factors and sex.
There is growing interest in examining the protective role of omega-3 polyunsaturated fatty acids in cognitive health among older adults. Yet, studies comparing lower with greater dietary intakes of omega-3 polyunsaturated fatty acids on neurocognitive outcomes remains somewhat inconclusive. It is speculated that the effect of omega-3 polyunsaturated fatty acids on cognitive function could be masked or confounded by the presence of other fatty acids in the diet including omega-6 polyunsaturated fatty acids, monounsaturated and saturated fatty acids. Untangling the interrelation between fatty acids that share similar biological pathways could improve our understanding of the specific effect of omega-3 polyunsaturated fatty acids on cognitive functions. Research also suggests that brain metabolic activity in aging males and females may not be the same. As a result, sex-related differences in cognitive function are also important considerations. Taking into account the evidence for sex-based differences in omega-3 fatty acid concentrations, it is surprising that few studies have examined the moderating role of sex in the association between omega-3 fatty acids and cognitive function.
Expanding on current knowledge, researcher Danielle Laurin (Centre de recherche du CHU de Québec-Université Laval, VITAM Research Centre and INAF) and colleagues evaluated the association between circulating concentrations of omega-3 polyunsaturated fatty acids and cognitive assessment performance, while taking into account the different types of omega-3 polyunsaturated fatty acids, other classes of fatty acids, and the potential effect modification by sex. In total, 386 healthy older adults from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive function, and processing speed were evaluated. Blood fatty acid concentrations were measured and grouped according to standard fatty acid classes.
Higher omega-3 polyunsaturated fatty acid concentrations were associated with better nonverbal memory and processing speed in models not including other fatty acids. The magnitude of these associations varied when other fatty acids were entered in the model. Associations with verbal episodic memory were limited to higher concentrations of eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid that is particularly important to brain structure and function, whereas there was no association between omega-3 polyunsaturated fatty acids and executive function. Higher omega-3 polyunsaturated fatty acids were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males.
The results of this cross-sectional study showed that higher concentrations of omega-3 polyunsaturated fatty acids were associated with better nonverbal episodic memory, processing speed, and, in some cases, verbal episodic memory. The extent to which omega-3 polyunsaturated fatty acids associated with cognitive functioning across cognitive domains was impactful on cognitive function depended on how omega-3 polyunsaturated fatty acids were categorized and whether additional fatty acids were included in the analytical model. The current findings suggest that other classes of fatty acids should be considered when evaluating the association between omega-3 polyunsaturated fatty acids and cognitive performance in healthy older adults. The beneficial effects of omega-3 polyunsaturated fatty acids may differ between males and females, depending on cognitive outcome, and warrant further investigation.
Caroline S Duchaine, Alexandra J Fiocco, Pierre-Hugues Carmichael, Stephen C Cunnane, Mélanie Plourde, Aurélie Lampuré, Benjamin Allès, Sylvie Belleville, Pierrette Gaudreau, Nancy Presse, Guylaine Ferland, Danielle Laurin, Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex, The Journal of Nutrition, Volume 152, Issue 9, September 2022, Pages 2117–2124, https://doi.org/10.1093/jn/nxac110.
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