Abstract
Background
Many observational studies on dietary omega-3 fatty acids (FAs) and cognition focused on docosahexaenoic acid (DHA), because its significant role in brain. There is growing interest in whether other omega-3 FAs may also display cognitive benefits.
Objectives
To examine the associations between the blood levels of three different omega-3 FAs (DHA; eicosapentaenoic acid [EPA]; and alpha-linolenic acid [ALA]) and 3-year changes in cognitive performance in a cohort of cognitively unimpaired individuals at high risk of Alzheimer’s disease (AD).
Methods
Prospective longitudinal study conducted in 323 participants from the ALFA (ALzheimer and FAmilies) Study. We determined the baseline levels of omega-3 FAs in red blood cells (RBCs) using gas-chromatography. Participants underwent a comprehensive neuropsychological battery at baseline and after 3 yrs. We studied cognitive outcomes as rate of change between visits. We first constructed multivariate models to examine the association between RBC-DHA and the preclinical Alzheimer’s cognitive composite (PACC) score, also examining the effect of gender, APOE-ε4 carriership, and AD pathology (defined cerebrospinal fluid amyloid-beta and tau). As exploratory analysis, we examined associations between RBC-EPA and RBC-ALA with PACC, as well as those between omega-3 FAs and composite z-scores for attention, executive functioning, episodic memory, visual processing, and language domains.
Results
RBC-DHA was associated with a positive (improved) global cognition (PACC) rate of change (estimate = 0.011, 95% confidence interval [CI] = 0.001;0.021, P = 0.024). No statistically significant interactions were observed for sex, APOE-ε4 carriership, or AD pathology. Higher RBC-ALA status was associated with positive rate of change (better performing) in visual processing (estimate = 0.425, 95% CI = 0.168;0.682, P = 0.001).
Conclusions
In individuals at risk of AD, RBC-DHA and RBC-ALA showed positive associations with longitudinal cognition. These findings add to the observational evidence linking omega-3 FAs with improved brain health.
Disclaimer: The study has been peer-reviewed and accepted but “In Press, Journal Pre-Proof” status and not published in final. The text could still change before final publication.