The carotenoids lutein and zeaxanthin were the most strongly associated with reduced risk of macular degeneration (MD). These are obtained primarily from dark green, leafy vegetables such as spinach, collard greens, kale, mustard greens, and turnip greens. Eating spinach and collard greens five or more times a week was found to noticeably reduce the risk of MD.
In addition to their antioxidant mechanism, lutein and zeaxanthin may help to protect the retina for any or all of the following reasons:
- They may protect against photodamage of the retina by filtering out blue light, which is not stopped by the cornea and lens, and which can damage the retina over time
- They may protect against peroxidation of fatty acids in the photoreceptor membrane
- They may protect the blood vessels that supply the macular region.
Lutein and zeaxanthin absorb best when taken with fat. For maximum absorption take supplements with any meal that contains fat or take along with any fatty acid supplements. The typical dose of lutein is between 10 and 20mg per day, and zeazanthin 1 to 4mg or higher per day.
Lutein / Zeaxanthin can help with the following
Cataracts / Risk
Supplementation with lutein (15mg three times per week), but not vitamin E (alpha-tocopherol 100mg three times per week), improved visual acuity and glare sensitivity in a study of 17 patients with age-related cataracts. No significant adverse
effects were observed during this two year long study. [Nutrition 2003;19(1): pp.21-4] This comment regarding vitamin E means that vitamin E, at the dose used in this study (alpha-tocopherol 100mg three times per week), did not produce any improvement, while lutein did.
People with diets higher in lutein and zeaxanthin had a lower risk of developing cataract. [American Journal of Clinical Nutrition, 1999, Vol. 69, pps. 272-277]
Macular Degeneration
Lutein, an antioxidant found in spinach and kale, works extremely well in protecting the retina against sunlight damage [Methods Enzymol 1992:213: pp.360-6]. Supplementation with 6mg of Lutein daily may decrease the occurrence of macular degeneration by more than 50% [JAMA 1994:272: pp.1413-20]. Lutein is one of the primary antioxidants for the macula rather than for the lens of the eye.
Six months of lutein 15mg per day, vitamin E 20mg per day and nicotinamide 18mg per day improved electrophysiologic measures of macular function in a pilot study of 30 patients with early age-related maculopathy as well as in eight healthy people who served as controls. [Ophthalmology 2003;110(1): pp.51-60]
The prevention of macular degeneration requires a lower dose of lutein and zeazanthin than does treating an already exisitng condition.
However, a study of 2,335 adults in Australia over a period of 5 years suggests that an increased intake of lutein, zeazanthin or other antioxidants may not have a protective effect. [Ophthalmology 2002;109(12): pp.2272-8]
Key
| Likely to help |
| Highly recommended |
Glossary
Macular Degeneration
Increasingly poor eyesight often accompanied by light sensitivity, distorted vision and a blank or dark patch in the center of vision.
Antioxidant
A chemical compound that slows or prevents oxygen from reacting with other compounds. Some antioxidants have been shown to have cancer-protecting potential because they neutralize free radicals. Examples include vitamins C and E, alpha lipoic acid, beta carotene, the minerals selenium, zinc, and germanium, superoxide dismutase (SOD), coenzyme Q10, catalase, and some amino acids, like cystiene. Other nutrient sources include grape seed extract, curcumin, gingko, green tea, olive leaf, policosanol and pycnogenol.
Retina
A 10-layered, frail nervous tissue membrane of the eye, parallel with the optic nerve. It receives images of outer objects and carries sight signals through the optic nerve to the brain.
Cornea
Transparent structure forming the anterior part of the eye.
Peroxidation
A type of oxidation that results in the formation of peroxides in body tissues which contain high proportions of oxygen.
Fatty Acids
Chemical chains of carbon, hydrogen, and oxygen atoms that are part of a fat (lipid) and are the major component of triglycerides. Depending on the number and arrangement of these atoms, fatty acids are classified as either saturated, polyunsaturated, or monounsaturated. They are nutritional substances found in nature which include cholesterol, prostaglandins, and stearic, palmitic, linoleic, linolenic, eicosapentanoic (EPA), and decohexanoic acids. Important nutritional lipids include lecithin, choline, gamma-linoleic acid, and inositol.
Milligram
(mg): 1/1,000 of a gram by weight.