Gut-eye axis and transporter-mediated strategies: enhancing retinal uptake of dietary nutrients

The blood-retinal barrier (BRB) stringently restricts the delivery of dietary nutrients to retinal tissues, presenting a major bottleneck for targeted nutritional intervention. This review systematically delineates three core pathways through which food-derived bioactive compounds overcome the limited delivery efficiency of the BRB: transporter-mediated active transport across the barrier, biotransformation by gut microbiota and the liver into bioactive metabolites with superior bioavailability, and gut-retina axis-mediated remote regulation of retinal homeostasis. An innovative focus is placed on "nutrient synergy" strategies, detailing their mechanisms for enhancing retinal targeting: absorption enhancement using biomimetic or lipid-based carriers, steering biotransformation via prebiotic combinations, and modulating transporter expression to facilitate ocular uptake. This synthesis provides a forward-looking framework for the rational design of BRB-targeted nutritional schemes, paving the way for their integration with precision nutrition and advanced delivery systems to achieve effective and personalized visual health support.