Vascular Roads to a Healthier Brain: Lutein Moderates the Influence of Arterial Stiffness on Cognitive Function.

BACKGROUND: Arterial stiffness, assessed via carotid-femoral pulse wave velocity (cfPWV), is a marker of vascular aging that may contribute to cognitive decline. Serum carotenoids, with antioxidant properties, may mitigate these effects, but their role in moderating neurovascular-cognitive relationships remains unclear. OBJECTIVES: This study examined: 1) associations between cfPWV and executive function, 2) the contribution of serum carotenoids in predicting cfPWV, and 3) whether carotenoids moderate the relationship between cfPWV and executive function. METHODS: A total of 60 adults (38.6 ± 17.57 y, 70% female) provided measures of cfPWV, serum carotenoids (lycopene, lutein, zeaxanthin, β-carotene, and β-cryptoxanthin), and executive function using Flanker and Go/No-Go tasks with event-related potentials (ERPs). Linear regression and Lindeman-Merenda-Gold metrics assessed associations and relative importance, whereas moderation analyses tested carotenoid interactions with cfPWV in predicting cognitive outcomes. RESULTS: Higher cfPWV was associated with slower P3 peak latency during Go target trials (β = 0.35, P = 0.02) and N2 latency during No-Go target trials (β = 0.34, P = 0.03). Serum lycopene was the strongest predictor of cfPWV (relative importance = 47.7%). Serum lutein uniquely moderated the relationship between cfPWV and executive function, such that higher lutein concentrations amplified associations between arterial stiffness and slower congruent reaction time (β = 0.48, P = 0.04) and P3 congruent peak latency (β = 0.53, P = 0.04) during the Flanker task, as well as P3 peak latency during Go (β = 0.53, P = 0.04) nontarget and No-Go (β = 0.77, P = 0.001) target trials. No other carotenoids showed significant moderation effects. CONCLUSIONS: Arterial stiffness impairs early-stage cognitive processing, as reflected by ERP latencies and reaction time. Lutein's selective moderation of these effects, despite lycopene's stronger association with cfPWV, suggests distinct vascular compared with neural protective mechanisms. Promoting lutein-rich diets may support neurovascular health, warranting intervention trials in at-risk populations.