A new study published in Nutrients shows that higher blood levels of the long-chain Omega-3 EPA and DHA are associated with cognitive benefits in older adults. In this study, researchers from the Boston Puerto Rican Health Study examined the prospective associations of omega-3 and omega-6 levels in red blood cells (RBCs) with measures of cognitive function in subjects who had an average age of 57.
Both omega-3 and omega-6 levels were measured using OmegaQuant’s proprietary methods at baseline. During a two-year period, researchers had 1032 subjects take the Mini-Mental State Exam (MMSE), while 865 subjects took other tests related to cognitive function. Changes in scores were assessed and correlated with the subjects’ omega-3 and omega-6 levels.
Omega-3 blood levels were not significantly associated with changes in MMSE score, but they were linked with better executive function, a facet of cognitive function that allows people to plan, organize and complete tasks.
Interestingly, blood levels of the long-chain omega-6 fatty acid, arachidonic acid (ARA), were associated with a 26% increased risk for developing cognitive impairment over two years of observation.
“The results of this study add to the growing body of evidence correlating blood levels of omega-3s to cognitive 
function,” said Dr. Bill Harris, CEO, OmegaQuant, and one of the study’s authors. “But perhaps more significant, studies like this show the importance of measuring blood levels of omega-3s as part of a study’s protocol. Hopefully this becomes the standard for all omega-3 studies moving forward.”
The Omega-3 index is expressed as a percent of total RBC fatty acids and is a long-term, stable marker of omega-3 status that accurately reflects tissue levels of EPA and DHA. An Omega-3 Index between 8% and 12% is considered the optimal range. This is the level at which fatal cardiovascular disease risk decreases dramatically.
Source: Bigornia SJ, Scott TM, Harris WS, Tucker KL. Prospective Associations of Erythrocyte Composition and Dietary Intake of n-3 and n-6 PUFA with Measures of Cognitive Function. Nutrients. 2018 Sep 6;10(9). pii: E1253. doi: 10.3390/nu10091253.