The Role Of Nutrition:

     Macular degeneration is the leading cause of blindness in people over the age of 55, affecting more than 10 million Americans.  The disease occurs when the central portion of the retina (the macula) deteriorates, resulting in impaired vision or blindness.  The good news is that leading researchers have identified specific dietary factors that can prevent, and even partially reverse, this devastating ocular disorder.

     Zeaxanthin is one of 700 plant pigments called carotenoids that provide much of the color in nature and our diet.  The carotenoids derive their name from the fact that the first pigment isolated, beta-carotene, was from carrots.  Beta-carotene is an important source of vitamin A, which is critical to vision.  Zeaxanthin and its closely related cousin, lutein, are called xanthophylls and are perhaps the third to seventh most prevalent carotenoids in the human diet (depending on fruit and vegetable selection).  Humans cannot synthesize these carotenoids and thus must obtain them from their diet.  Zeaxanthin and lutein have been recently called "conditionally essential nutrients" because of their critical protective functions in the eye

Guarding Against Light Damage

     Plants synthesize zeaxanthin and lutein to harvest light energy and protect against excessive light.  It now appears that humans also utilize these pigments to protect the eye from excessive interaction with the damaging effects of light.  This function of zeaxanthin is analogous to a set of "nature's sunglasses" for the tissues of the eye.  In plants, lutein is most often used to help green leafy tissues harvest light safely.

     While plants use zeaxanthin to safely harvest light, they more importantly use zeaxanthin to protect against harmful light levels.  Dark green leafy vegetables contain large amounts of both pigments but have much more lutein compared to zeaxanthin.  Zeaxanthin is more predominant in many of the yellow, orange, and red fruits and vegetables such as peppers, corn, and peaches.

     Both lutein and zeaxanthin absorb the very high-energy and most damaging portions of the light spectrum (ultraviolet blue).  This absorption of the high-energy spectrum is critical to the protection of the lens, retina, and macular portions of the eye.

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