Astaxanthin the super nutrient
Astaxanthin (pronounced asta-ZAN-thin) has been described as a 'super-nutrient' - the most powerful antioxidant ever discovered for eye health1,2 and may play a significant role in helping to arrest the development of Age Related Macular Degeneration (AMD).
Astaxanthin stands alone as the 'super-nutrient' for eye health because it is far more effective than other carotenoids at singlet-oxygen quenching which reduces the damaging effects of sunlight; crosses the blood-brain barrier and the blood-retinal barrier which increases eye health; is a powerful scavenger of harmful free radicals; is a potent UVB absorber; and is not associated with any adverse reactions.
Your macula sits in the center of the tissue that lines the back of your eye. Oxidative stress can damage the rods and cones, the cells that make up the macular tissue, and damage to these light receptor cells can cause a permanent loss of central vision. Macular degeneration does not cause total blindness because peripheral visual fields are not affected, but reading, driving and recognising faces eventually becomes impossible.
All tissues within your eye require adequate nutrients and oxygen from an uninterrupted blood supply to function properly and provide you with clear vision. The macula is sensitive to free-radical damage and lack of blood. Carotenoids are colorful pigments found in fruits, vegetables and seafood that are powerful antioxidants and offer protection to the small blood vessels that supply the eye. Some carotenoids, such as Astaxanthin, are particularly powerful and have a predilection for the macula.
Carotenoids in the RetinaOne of the main type of carotenoids are the xanthophylls, most of which can pass the blood-brain barrier and be absorbed by the tissues of your retina. The best known xanthophylls are lutein and zeaxanthin, although Astaxanthin may be the most powerful.
Quenching Damaging Singlet-Oxygen MoleculesA 1996 report by Dr N Shimidzu found that natural Astaxanthin is 550 times more effective than Vitamin E, 11 times more effective than Beta Carotene, 3 times more effective than lutein at quenching singlet-oxygen, which is a particularly damaging form of oxygen molecule.
Scavenging for Free RadicalsFree radicals are generated by continuous or excessive exposure to light and the highly oxygenated environment of the normal eye. Free radicals oxidize the polyunsaturated fatty acids in the retina, which leads to functional impairment of the retinal cell membranes, causing temporary and permanent damage to the retinal cells. Once the retina is damaged, it cannot be replaced.
A 2001 report prepared by Dr. D. Bagchi of the Creighton University School of Health Sciences found that as an antioxidant, Astaxanthin is 14 times more potent than vitamin E, 54 times more potent that beta-carotene and 65 times more potent than vitamin C in scavenging free radicals. In addition to protecting blood vessels, lutein, zeaxanthin and astaxanthin absorb certain frequencies of UV light and protect the retinal photoreceptor cells from damage. In general, the more carotenoids the macula contains, the better the protection against light damage and resistance to degeneration.
Special Properties of AstaxanthinIn moderate amounts, lutein and zeaxanthin are strong antioxidants, but in high concentrations caused by supplemental mega-dosing, these carotenoids can act as pro-oxidants and may actually cause further damage. According to a 2006 article published in the "Journal of Natural Products," Astaxanthin does not exhibit pro-oxidant activity, despite being a powerful antioxidant and may be the safest carotenoid supplement for eye health. Further, Astaxanthin's ability to concentrate in the retinal macula makes it a good choice to specifically combat macular degeneration.
SourcesAstaxanthin is the carotenoid responsible for the red color in salmon, lobster, krill, crab, other shell fish and H. pluvialis, which is an algae used to make the natural supplemental form.
Astaxanthin and CataractsAntioxidants may help prevent cataracts, an eye condition that stems from the breakdown of proteins that compose the lens that sits behind your iris. This breakdown process, called oxidative stress, results from free radicals, rogue oxygen molecules that can damage healthy cells. This process causes the lens to turn opaque and turn your vision cloudy. The antioxidant component of Astaxanthin may help slow this process or have some effect on preventing oxidative stress. Medications and supplements will not reverse cataracts, but doctors can treat cataracts with surgery and restore vision changes from the cloudy lens.
References1. Capelli, B, Cysewski G. (2007) "Natural Astaxanthin: King of the Carotenoids", Cyanotech Corporation, ISBN-13: 978-0-9792353-0-6.
2. Mercola Dr, (2011). "Astaxanthin: Number one Supplement", http://www.healthybodydaily.com, accessed 20/01/2011.
3. Martin, H., Jager, C., Ruck, C., Schimdt, M. (1999). "Anti- and Pro-oxidant Properties of Carotenoids." J. Prakt. Chem. 341(3):302-308.
4. Shimidzu, N., Goto, M., Miki, W. (1996). "Carotenoids as singlet oxygen quenchers in marine organisms." Fisheries Science. 62(1): 134-137.
5. Bagchi, D. (2001). "Oxygen Free Radical Scavenging Abilities of Vitamins C, E, B-Carotene, Pycnogenol, Grape Seed Proanthocyanidin Extract, Astaxanthin and BioAstin in Vitro." On file at Cyanotech Corporation.