Omega-3 supplementation and loneliness-related memory problems: secondary analyses of a randomized controlled trial

Abstract

Objective: Loneliness enhances risk for episodic memory declines over time. Omega-3 supplementation can improve cognitive function for people experiencing mild cognitive difficulties. Accordingly, we explored whether omega-3 supplementation would attenuate loneliness-related episodic memory problems.

Methods: Participants (n = 138) from a parent randomized controlled trial were randomized to the placebo, 1.25 grams/d of omega-3, or 2.50 grams/d of omega-3 conditions for a 4-month period. They completed a baseline loneliness questionnaire and a battery of cognitive tests both at baseline and at the end of the randomized controlled trial.

Results: After adjustment for baseline verbal episodic memory scores, lonelier people within the placebo condition had poorer verbal episodic memory postsupplementation, as measured by immediate (b = -0.28, t (117) = -2.62, p = .010) and long-delay (b = -0.06, t (116) = -2.07, p = .040) free recall, than their less lonely counterparts. This effect was not observed in the 1.25- and 2.50-grams/d supplementation groups (all p values > .10). The plasma omega-6:omega-3 ratio data mirrored these results. There were no loneliness-related effects of omega-3 supplementation on short-delay recall or the other cognitive tests (all p values > .32).

Conclusion: These results suggest that omega-3 supplementation attenuates loneliness-related verbal episodic memory declines over time and support the use of exploring novel interventions for treating episodic memory problems among lonely people.

Trial registration: clinicaltrials.gov Identifier: NCT00385723.

Figures

Figure 1. Loneliness by supplementation group predicting immediate free recall

Note. Higher CVLT numbers represent more words recalled, and thus better verbal episodic memory. The values depicted are the estimated marginal means at average levels of baseline immediate free recall, marital status, BMI, and activity levels. The error bars refer to the standard error of the mean. ns means non-significant, *p≤.05.

Figure 2. Loneliness by supplementation group predicting long-delay free recall

Note. Higher CVLT numbers represent more words recalled, and thus better verbal episodic memory. The values depicted are the estimated marginal means at average levels of baseline long-delay free recall scores, marital status, BMI, and activity levels. The error bars refer to the standard error of the mean. ns means non-significant, **p≤.01.