Supplementation with lutein and zeaxanthin increases macular pigment optical density and cognitive performance in healthy teenagers in a randomized, double-blind, placebo-controlled trial.

Studies in adults have demonstrated that lutein and zeaxanthin (LZ) supplementation may improve eye and cognitive function, although limited studies have been conducted in teenagers. In this two-arm, 6-month, parallel-group, randomized, double-blind, placebo-controlled trial, supplementation with a placebo (sunflower oil) or lutein (10 mg) and zeaxanthin (2 mg) was examined for its effects on macular pigment optical density (MPOD), cognitive function, and sleep in teenagers aged 13 to 18 years with high screen use and consuming a diet low in fruits and vegetables. Eighty-two teenagers were assigned to receive LZ or a placebo daily. Outcome measures included changes in MPOD (primary outcome), cognitive performance (Test of Memory and Learning Version 2, National Institute of Health Cognition Toolbox, and 3D Aim Trainer), and self-report measures of attention and sleep. It was hypothesized that LZ supplementation would be associated with increases in MPOD and improvements in cognitive function. Compared to the placebo, LZ were associated with greater improvements in MPOD in the left (P = .010) and right eyes (P = .004), tests of attention (P = .026) and processing speed (P = .034), but not in the test of visual reasoning (P = .728), nonverbal memory (P = .999), or a first-person shooter game (P = .873). Moreover, there were no between-group differences in changes in self-report measures of attention and sleep. LZ supplementation was well-tolerated with no significant adverse reactions reported. This is the first published study to demonstrate that supplementation with LZ in teenagers for 6 months can increase MPOD and some aspects of cognitive performance. Further research on teenagers with impairments in cognitive performance and sleep quality will be important to extend the results of this study. Trial registration: This trial was registered prospectively on January 20, 2025 with the Australian and New Zealand Trials Registry (ANZCTR) (ACTRN12625000047493).