The role of lutein and zeaxanthin in protection against age-related macular degeneration

Lutein and zeaxanthin are dietary carotenoids derived from dark green leafy vegetables and orange and yellow fruits and vegetables that form the macular pigment of the human eye. They are specifically concentrated in the foveal region where they are thought to protect against age-related macular degeneration (AMD) through antioxidant and light protective mechanisms. Over 600 carotenoids are found in nature, and 30-50 are part of the normal human diet, yet only 10-15 are routinely detectable in the human serum, and just two carotenoids, lutein and zeaxanthin and their various metabolites, are present in the retina. The biochemical mechanisms underlying this remarkable selectivity of uptake into the eye have been a focus of my laboratory for the past two decades. The pathways these dietary xanthophylls must take from the gut to the macula will be reviewed with special attention to the macular carotenoids' specific binding proteins. The key findings of the recently completed Age Related Eye Disease Study 2 (AREDS2), which examined the benefits of lutein, zeaxanthin, and omega-3 fatty acids in the prevention of advanced AMD in eyes of patients with a high risk of visual loss from progressive AMD, will also be discussed.