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

BACKGROUND & AIMS

Accumulating evidence suggests that omega-3 fatty acids (ω-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 ω-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 meso-zeaxanthin, 2 mg zeaxanthin) and 15 mg vitamin E or placebo for 24 months in a double-blind, placebo-controlled, randomised clinical trial.

RESULTS

Following 24-month supplementation, individuals in the active group (n = 30; aged 69.03 ± 4.41 years; 56.7% female) recorded significantly fewer errors in working memory tasks than individuals receiving placebo (n = 30; aged 69.77 ± 3.74 years; 70% female) (point estimate effect sizes ranged 0.090-0.105). 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 ω-3FA concentrations were also observed in the active group versus placebo (point estimate effect sizes ranged 0.078-0.589). Moreover, the magnitude of change of carotenoid concentrations in tissue, and ω-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 ω-3FAs may prove beneficial in reducing cognitive decline and dementia risk in later life.

STUDY ID NUMBER

ISRCTN10431469; https://doi.org/10.1186/ISRCTN10431469.

Informations de copyright

Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.

Déclaration de conflit d'intérêts

Conflict of Interest Rebecca Power: RP has performed consultancy work for MacuHealth LLC™ (Birmingham, MI, USA). RP is funded in part by the Howard Foundation (registered with the Charity Commission of England & Wales #285822), hereafter “Howard Foundation”. These organisations have an interest in commercially available supplements containing the macular carotenoids. RP is also funded by a joint research centre grant from Science Foundation Ireland (SFI) and the Department of Agriculture, Food, and Marine on behalf of the government of Ireland under grant #16/RC/3835—VistaMilk to develop commercial dairy products enriched in carotenoids. John M. Nolan does consultancy work as a Director of NOW Science Consultancy Ltd. for companies with an interest in food supplements. Alfonso Prado-Cabrero: APC has performed consultancy work for MacuHealth LLC™ and the Howard Foundation. APC has also been involved in a Commercialisation Fund Programme from Enterprise Ireland to develop a biotechnological process to produce carotenoids and the fatty acids EPA and DHA. APC is currently supported by grant #16/RC/3835—VistaMilk. Robert Coen, Warren Roche and Tommy Power declare no conflicts of interest. Ríona Mulcahy does consultancy work on behalf of the Howard Foundation.