Abstract
- Background
Lutein and zeaxanthin are fat-soluble dietary carotenoids that selectively accumulate in high concentrations within human neural tissues, including the brain. A growing body of scientific literature has established robust associations between status and intake of these macular carotenoids and preserved cognitive function. However, intervention data evaluating their targeted cognitive benefits in populations with subjective cognitive decline remain necessary. This randomized controlled trial was designed to examine the effects of daily lutein and zeaxanthin supplementation on cognitive performance in community-dwelling adults presenting with self-reported cognitive complaints.
- Methods
A rigorous two-arm, parallel-group, 6-month, randomized, double-blind, placebo-controlled clinical trial design was implemented. Ninety adult volunteers aged 40 to 75 years were randomly assigned to receive either a daily oral dose of 10 mg lutein and 2 mg zeaxanthin or a matched placebo for six consecutive months. Comprehensive primary and secondary outcome measures were evaluated, including computer-based cognitive task batteries, the Cognitive Failures Questionnaire (CFQ), the Behavior Rating Inventory of Executive Function (BRIEF), the Profile of Mood States (POMS), and the Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) health status profile.
- Results
Compared to the placebo group, daily supplementation with lutein and zeaxanthin was associated with statistically significant improvements in visual episodic memory ($P = 0.005$) and visual learning ($P = 0.001$). However, no other statistically significant between-group differences were observed across the remaining computer-based cognitive performance tests or standardized self-report questionnaires evaluating executive function, memory failures, mood states, or physical health-related quality of life. The carotenoid supplementation regimen was exceptionally well-tolerated, with no reports of significant adverse clinical events or side effects.
- Conclusions
Six-month supplementation with lutein and zeaxanthin significantly enhances visual memory and learning performance in community-dwelling adults experiencing self-reported cognitive complaints, while exhibiting an excellent safety profile. Nonetheless, it produces no concurrent measurable effects on other computerized cognitive domains or self-reported metrics of cognition, mood, or physical function.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8891800/