Improving omega-3 status at early midlife may be critical for long-term cognitive function, says recent study

Photo © iStockphoto.com/Jacob Wackerhausen

A recent study¹ found an association between blood omega-3 levels and cognitive function in middle-aged subjects. In the study, researchers used participants from the Third-Generation and Omni 2 cohorts of the Framingham Heart Study attending their second examination. These cohorts were made up of 2,183 dementia and stroke-free participants with a mean age of 46 years. Researchers measured Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations using gas chromatography, calculated the Omega-3 Index, then used linear regression models to relate omega-3 fatty acid concentrations to brain MRI measures (i.e., total brain, total gray matter, hippocampal, and white matter hyperintensity volumes) and cognitive function (i.e., episodic memory, processing speed, executive function, and abstract reasoning). Interactions between omega-3 fatty acid levels and APOE genotype (e4 carrier vs. non-carrier) – a genetic risk factor for dementia, and Alzheimer’s disease – on MRI and cognitive outcomes were also tested.

Results showed that higher DHA concentrations or Omega-3 index were associated with larger hippocampal volumes in APOE-e4 non-carriers, whereas higher EPA concentrations were related to better abstract reasoning in APOE-e4 carriers. Additionally, higher levels of all omega-3 predictors were related to lower white matter hyperintensity burden, but only in APOE-e4 carriers.

"The results of this study show that low red blood cell DHA levels are associated with smaller brain volumes and a ‘vascular’ pattern of cognitive impairment, even in persons free of clinical dementia. This suggests that intervening early and maintaining an optimal Omega-3 Index (8% or higher) could play an important role in staving off cognitive decline, as well as dementia and Alzheimer’s in the long-term," commented William S. Harris, PhD, FACN, president of the Fatty Acid Research Institute (FARI), and one of the study’s authors.

Historically, results from dietary intervention studies using omega-3 EPA and DHA have been inconsistent, despite the beneficial associations observed for brain outcomes in population-based and experimental studies. The researchers believe this is because dietary interventions are carried out too late for significant improvements to occur in symptomatic subjects. Therefore, omega-3s may be most beneficial to preserve brain health from early midlife.

Reference

1. Satizabal CL et al. “Association of red blood cell omega-3 fatty acids with MRI markers and cognitive function in midlife: The Framingham heart study.” Neurology, Published online ahead of print on October 5, 2022, DOI: https://doi.org/10.1212/WNL.0000000000201296