Omega-3 fatty acid, carotenoid and vitamin E supplementation improves working memory in older adults: A randomised clinical trial

Rebecca Power, John M. Nolan, Alfonso Prado-Cabrero, Warren Roche , Robert Coen, Tommy Power, Ríona Mulcahy

Summary
Background & aims: Accumulating evidence suggests that omega-3 fatty acids (u-3FAs), carotenoids and
vitamin E can improve cognitive performance. However, their collective impact on cognition has not yet
been investigated in healthy individuals. This study investigated the combined effect of u-3FA, carotenoid
and vitamin E supplementation on the cognitive performance of older adults.
Methods: Cognitively healthy individuals aged _65 years consumed daily 1 g fish oil (of which 430 mg
docosahexaenoic acid, 90 mg eicosapentaenoic acid), 22 mg carotenoids (10 mg lutein, 10 mg mesozeaxanthin, 2 mg zeaxanthin) and 15 mg vitamin E or placebo for 24 months in a double-blind, placebocontrolled, randomised clinical trial.
Results: Following 24-month supplementation, individuals in the active group (n ¼ 30; aged 69.03 ± 4.41
years; 56.7% female) recorded significantly fewer errors in working memory tasks than individuals receiving placebo (n ¼ 30; aged 69.77 ± 3.74 years; 70% female) (point estimate effect sizes ranged 0.090 e0.105). Interestingly, as the cognitive load of the working memory tasks increased, the active group outperformed the placebo group. Statistically significant improvements in tissue carotenoid concentrations, serum xanthophyll carotenoid concentrations and plasma u-3FA concentrations were also observed in the active group versus placebo (point estimate effect sizes ranged 0.078e0.589). Moreover, the magnitude of change of carotenoid concentrations in tissue, and u-3FA and carotenoid concentrations in blood were related to the magnitude of change in working memory performance.
Conclusion: These results support a biologically plausible rationale whereby these nutrients work synergistically, and in a dose-dependent manner, to improve working memory in cognitively healthy older adults. Increasing nutritional intake of carotenoids and u-3FAs may prove beneficial in reducing cognitive decline and dementia risk in later life.

Power et al 2022, doi: 10.1016/j.clnu.2021.12.004