Lutein, a natural yellow pigment found mostly in colorful vegetables, is classified as a carotenoid and a xanthophyll. Carotenoids act as antioxidants: substances that prevent free radicals from damaging cells in the eye and elsewhere. Lutein is one of several carotenoids found in large amounts in the eye. Lutein may have several benefits in maintaining eye health.
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In plants, lutein keeps plants from absorbing too much high-energy light, called blue light, which can damage cells. In the eye, lutein appears to act in a similar manner, absorbing excess blue light before it reaches the inner layers of the eye. The antioxidative effects of lutein may also protect the eye from damage.
Benefits
Lutein has been tested as a prevention agent or treatment for several different eye conditions, including macular degeneration, cataracts and retinitis pigmentosa, a condition that first causes loss of night vision and peripheral vision but can progress to total vision loss. A study reported in the March 2008 "Archives of Ophthalmology," conducted by researchers from the University of Wisconsin, examined data from 1802 women aged 50 to 79 in the Women's Health Initiative Observational Study. Researchers found that women with a high dietary intake of lutein and zeaxanthin, another carotenoid prevalent in the eye, reduced their risk of developing nuclear cataracts by 23 percent. Cataracts, which involve clouding of the lens in the eye, cause blurred vision and loss of night vision. An Australian study reported in the February 2008 issue of "Ophthalmology" found that a high dietary intake of lutein and zeaxanthin also reduced the risk of developing age-related macular degeneration, which results in central vision loss, in men and women over age 49.
Sources
Dietary sources of lutein include green leafy vegetables such as spinach and kale. Greens such as dandelion, collard and turnip greens also supply good amounts of lutein. Lutein supplementation benefits have not yet been well established, but the National Eye Institute began the five-year AREDS 2 study in 2006 to assess the benefits of lutein, zeaxanthin and fish oils on age-related macular degeneration. Lutein 10 mg is the dose being used in the study; some experts suggest taking 6 mg per day for eye benefits, All About Vision reports.
Risks
The only definite risk of high lutein intake noted to date is a yellowish coloration to the skin, called carotemia. This is unrelated to jaundice, a potentially serious yellow coloration related to liver disease. However, a study on the risks of lutein and several other carotenoids found a potential link between lutein intake and lung cancer in smokers. Researchers for the study, published in the February 2009 "American Journal of Epidemiology" recommended that smokers not take lutein supplements.
References
- All About Vision: Lutein and Zeaxanthin: Eye and Vision Benefits
- NYU Langone Medical Center: Lutein
- Johns Hopkins: Lutein Supplements May Improve Vision
- PubMed.gov: Associations Between Age-Related Nuclear Cataract and Lutein and Zeaxanthin in the Diet and Serum in the Carotenoids in the Age-Related Eye Disease Study, an Ancillary Study of the Women's Health Initiative
- PubMed.gov: Dietary Antioxidants and the Long-term Incidence of Age-related Macular Degeneration: the Blue Mountains Eye Study
- "American Journal of Epidemiology;" Long-term Use of b-Carotene, Retinol, Lycopene, and Lutein Supplements and Lung Cancer Risk: Results From the VITamins And Lifestyle (VITAL) Study; Jessie Satia; February 2009
