Randomized, Placebo-Controlled, Single-Blind Study of Lutein Supplementation on Carotenoid Status and Cognition in Persons with Multiple Sclerosis

Abstract

Background: Multiple sclerosis (MS) is traditionally managed using disease-modifying pharmaceutical therapies as a first line approach for treatment, yet there is increasing interest in lifestyle factors, particularly diet, for managing disease outcomes. Lutein has neuroprotective properties in healthy adults, but no previous research has examined the effects of lutein supplementation in persons with MS.

Objectives: This study aimed to investigate the efficacy of 4-mo lutein supplementation on carotenoid status and cognition in persons with relapse-remitting MS (RRMS).

Methods: A randomized controlled, single-blind research design was used among adults with RRMS (N = 21). Participants were randomized into placebo (n = 9) or treatment (20-mg/d lutein, n = 12) groups with outcomes measured before and after 4 mo. Macular pigment optical density (MPOD) was assessed using heterochromatic flicker photometry. Skin carotenoids were assessed using reflection spectroscopy. Serum lutein was measured using high-performance liquid chromatography. Cognition was assessed via the Eriksen flanker with event-related potentials, spatial reconstruction, and the symbol digit modalities tests.

Results: There was a significant group by time interaction for MPOD (F = 6.74, P = 0.02), skin carotenoids (F = 17.30, P < 0.01), and serum lutein (F = 24.10, P < 0.01), whereby the treatment group improved in all carotenoid outcomes. There were no significant group by time interactions for cognitive and neuroelectric outcomes. However, increase in MPOD was positively associated with accuracy during the flanker incongruent trials (r = 0.55, P = 0.03) and the spatial memory task (r = 0.58, P = 0.02) among treatment participants.

Conclusions: Lutein supplementation increases carotenoid status among persons with RRMS. There is no significant effect on cognitive function but change in macular carotenoids is selectively associated with improved attention and memory. This study provides preliminary support for a fully powered study targeting retinal and neural carotenoids for cognitive benefits in persons with MS. This trial was registered at clinicaltrials.gov as NCT04843813.

Keywords: carotenoids; cognition; lutein; macular pigment; multiple sclerosis.