A study published in the February 28 issue of the journal Neurology provides more evidence that high dietary consumption of omega-3 fatty acids, found in fish such as salmon and tuna, may protect the brain against cognitive impairment.
The research team, led by Dr. Zaldy S. Tan, found that healthy older adults 58-76 (m = 67) with the lowest red blood cell (RBC) levels of the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) had “older” brains than their peers as well as a vascular pattern of cognitive impairment. Researchers examined the relationship of RBC fatty acid levels in 1,575 Framingham Heart Study participants who were dementia-free to MRI brain volumetrics and neuropsychological measures of verbal memory, visuospatial memory, abstract reasoning, attention and executive functioning.
Previous research has relied on measures of omega-3 fatty acids in blood plasma, a “snapshot” indicator of how much of the essential nutrients have been consumed in the past few days. In comparison, this study examined RBC fatty acid composition, which reflects average dietary intake across the RBC lifespan of up to 120 days.
Participants with the lowest DHA and EPA levels had significantly lower total brain volumes, equivalent to about 2 years of structural brain aging, and greater white matter hyperintensity volumes, which have been associated with vascular disease. Additionally, these participants performed poorer on tests of visual memory, executive function, and abstract thinking, all suggestive of vascular changes.
Findings support previous research suggesting that fish consumption is associated with lower risk of cognitive decline and dementia. Omega-3 fatty acids may benefit the vasculature and the brain in multiple ways, such as lowering blood pressure, reducing the risk of thrombosis, reducing inflammation, and lowering serum triglyceride levels.