Abstract
Background:
Long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are reported to be beneficial for cognition, but limited consumption of some fish is recommended due to high concentrations of heavy metals and persistent organics.
Objective:
We investigated aimed to determine whether dietary ω-3 PUFAs from fish consumption is associated with higher cognitive scores in older adults and explored the associations of mixtures of ω-3 PUFAs and blood concentrations of lead, cadmium, selenium, and methylmercury on cognitive performance.
Methods:
We conducted a cross-sectional study with data from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2014, assessing cognitive scores of immediate recall, delayed recall, and executive function in adults 60 years and older (n = 3,123). We performed multivariate linear regressions and mixture models utilizing the quantile-based g-computation method to identify associations between monthly fish consumption or dietary ω-3 PUFAs with blood concentrations of lead, cadmium, methyl mercury, and selenium on cognitive scores.
Results:
Fish consumption had significant positive associations with all three cognitive scores, while dietary ω-3 PUFAs were only significantly associated with the Digit Symbol Substitution Test (DSST scores). Mixture analysis showed significant positive associations with DSST scores for fish consumption (β = 0.88, 95% CI = 0.48, 1.29), and dietary ω-3 PUFAs (β = 0.41, 95% CI = 0.03, 0.78) with positive component weights for fish consumption, dietary ω-3 PUFAs, and blood selenium and negative component weight for blood cadmium concentrations.
Conclusions:
Our findings support dietary recommendations for older adults to consume fish to maintain cognitive function, likely due to biomolecular actions of ω-3 PUFAs that increase neuronal membrane fluidity, have antioxidation activity, and restore cell damage. The combination of selenium and fish consumption or ω-3 PUFAs was associated with reduced decline in cognitive scores and less negative associations from exposures to lead, cadmium, and mercury compounds.
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