A 24-months of supplementation with omega-3 fatty acids, carotenoids and vitamin E led to improvements in working memory of cognitively healthy older adults, according to the findings of a double-blind, placebo-controlled, randomized clinical trial published in Clinical Nutrition. Rebecca Power et al. undertook this trial to assess the synergistic effects of omega-3 fatty acids, carotenoid and vitamin E supplementation on the cognitive performance.

Participants (cognitively healthy older adults) were segregated into two groups: (i) Active group: (n=30; age 69.03±4.41years; 56.7% female) Included people who consumed daily 1 g fish oil (90 mg eicosapentaenoic acid, 430 mg docosahexaenoic acid), 22 mg carotenoids (2 mg zeaxanthin, 10 mg meso-zeaxanthin, 10 mg lutein) and 15 mg vitamin E, and (ii) Placebo group (n=30; aged 69.77±3.74 years; 70% female).

After twenty-four months of supplementation, people in the active group reported considerably reduced errors in the working memory tasks compared to people in the placebo group. As cognitive load of working memory tasks elevated, the active group was found to outperform placebo group.

The active group exhibited remarkable improvements in the serum xanthophyll carotenoid concentrations, tissue carotenoid concentrations, and plasma omega-3 fatty acids concentrations when compared to the placebo group. Furthermore, magnitude of alteration of carotenoid levels in tissue and alteration in levels of omega-3 fatty acids and carotenoid in blood were associated with magnitude of alteration in the working memory performance.

The findings thus supported the biologically plausible rationale where nutrients such as  carotenoids, vitamin E, and omega-3 fatty acids work synergistically in a dose-dependent way for improving cognitive performance.