Beyond Bioavailability: Lutein Delivery Systems and the Shift Toward Precision Nutrition

Lutein is a xanthophyll carotenoid and dietary pigment with an established role in ocular health and potential neuroprotective, hepatoprotective, cardiovascular, and anti-inflammatory effects. Despite this broad biological relevance, average lutein intake in Western populations remains approximately 1–2.2 mg/day, with no established RDI or RDA, while oral bioavailability is limited under typical dietary conditions. Delivery systems, including lipid-based systems, biopolymer matrices, colloidal nanocarriers, and stimuli-responsive smart platforms, have emerged as practical strategies to improve lutein stability, protect it during gastrointestinal transit, and enhance bioaccessibility and systemic exposure. However, genetic variation in uptake-related genes, including SCARB1 and CD36, alongside gut microbiome composition and body composition, may contribute to inter-individual variability in lutein response. Most existing reviews have examined lutein’s health effects, encapsulation, and delivery systems; few have addressed whether formulation performance differs meaningfully among individuals. This review integrates lutein’s chemistry, biological activity, and delivery systems, and considers how formulation design might be matched to individual absorption profiles rather than simply improving average bioavailability across a population. It distinguishes demonstrated delivery outcomes from proposed personalized applications and highlights the human evidence needed to validate this approach.