(HealthDay News) – In adults without clinical dementia, low red blood cell (RBC) levels of omega-3 fatty acids are associated with smaller brain volumes and lower scores on tests of visual memory and executive function, according to a study published in the Feb. 28 issue of Neurology.

Zaldy S. Tan, MD, MPH, from the David Geffen School of Medicine at the University of California in Los Angeles, and colleagues investigated the association between RBC fatty acid levels in 1,575 dementia-free participants (aged 67±9 years) and performance on cognitive tests and volumetric magnetic resonance imaging. In model A, adjustments were made for age, gender, and education; and in additional models, adjustments were also made for APOE ε4 and plasma homocysteine, for physical activity and body mass index, and for traditional vascular risk factors.

The researchers found that participants with RBC docosahexaenoic acid (DHA) in the lowest quartile had significantly lower total brain volume and greater white matter hyperintensity volumes, compared to those with RBC DHA levels in the second to fourth quartiles. The association with total brain volume persisted after multivariable adjustments. Participants with DHA and ω-3 index (RBC DHA + eicosapentaenoic acid [EPA]) levels in the lowest quartile had lower scores on tests of visual memory, executive function, and abstract thinking in all models, compared to those with levels in the second to fourth quartiles.

“Lower levels of RBC DHA and EPA in late middle-age were associated with markers of accelerated structural and cognitive aging,” the authors write.

Several authors disclosed financial ties to the pharmaceutical and biotechnology industries.

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