The eye is one of the most oxidatively stressed parts of the body, and the retina is our most metabolically active tissue. The retina has a constantly high need for oxygen and energy, yet depends on miniscule, delicate blood vessels to deliver nourishment. The eye receives light and translates it into nerve impulses, yet virtually all of its specialized structures are highly susceptible to damage from light exposure. Eyes’ nutritional and energetic demands also cause them to be hypersensitive to high blood pressure, hyperglycemia, and increased ocular pressure—each of which may relate strongly to lifestyle inputs.
Astaxanthin is a xanthophyll, an oxygenated non-vitamin A carotenoid that is formed by microalgae and phytoplankton species like Haematococcus pluvialis and Chlorella zofingiensis. These marine plants are consumed by fish and shellfish such as shrimp, crayfish, salmon, crab, and lobster, and the astaxanthin they consume confers bright pink coloration to their flesh and shells.
Astaxanthin is composed of two carbon rings bridged by a conjugated 18-carbon chain, with each of these structures possessing multiple active groups. This complex and stereochemically dynamic molecular shape gives astaxanthin a broad range of lipophilic as well as hydrophilic properties, along with the optimal length for spanning cell membranes. As a result, astaxanthin can absorb and help neutralize reactive species originating either inside or outside cells—an extraordinary protective capacity that is rare among antioxidants.