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What is it?
Lutein and zeaxanthin are carotenoids found in highest concentration in the macular region of the eyes (the back of the eye where the retina is located), where they are believed to help filter out damaging blue light and prevent free radical damage to the delicate structures in the back of the eye.
Claims
Because antioxidants can provide increased protection against the oxidizing ultraviolet radiation of the sun, anybody that spends time outdoors exposed to the sun should be concerned with the potential for ultraviolet radiation to damage eye health and impact vision. Lutein and zeaxanthin are the only carotenoids that become concentrated in the retinal region of the eye known as the macula. High dietary intake of lutein-rich fruits and vegetables has been associated with a significant reduction in macular degeneration the leading cause of blindness in Americans over the age of 65.
Scientific Support
Sunlight exposure has been linked to vision loss and to an increased risk of age-related macular degeneration (ARMD) the leading cause of blindness in people over 65 years of age. In the U.S., about 13-14 million people have evidence of ARMD, with almost 30% of those over the age of 75 affected.
The macula is a specialized region in the back of the eye (retina) which allows you to clearly see fine details. As cells in the macula region breakdown, you begin to lose sight in the center of your field of vision and may develop problems seeing in bright or dark conditions. In addition to sunlight exposure, age, smoking and diet have been identified as risk factors for ARMD.
Although there isnt much you can do about your age as a risk factor for ARMD, you can modify your risk from the sun (wear sunglasses or wide-brimmed hats), smoking (dont), and diet (consume enough antioxidants). In terms of diet, it is clear that individuals who consume fruits and vegetables at least once per day have a significantly reduced risk of developing ARMD. It is also well known that higher levels of antioxidants in the blood are associated with reduced rates of ARMD. Among the dozens of dietary antioxidants, however, carotenoids appear to have the greatest effect and two carotenoids in particular, Lutein and Zeaxanthin, seem to be most effective.
The best dietary sources of antioxidants in general, and carotenoids specifically, are fruits and vegetables and the more brightly colored, the better. Lutein and zeaxanthin are yellow pigments found in high concentrations in yellow fruits and vegetables (obviously) as well as in dark green, leafy vegetables. In particular, spinach, kale and collard greens contain high levels of these two carotenoids so high that individuals with the highest spinach consumption reduce their risk of developing ARMD by almost 90%!
Both lutein and zeaxanthin seem to reduce the risk of ARMD and protect overall eye health by at least two different routes. First, both of these carotenoids are absorbed from the diet into the circulation and eventually end up concentrated specifically in the eye (in the macular region of the retina). It is interesting to note that lutein and zeaxanthin are the only carotenoids known to concentrate specifically in the eye tissues. The high levels of these carotenoids in the eye serve to protect tissues by minimizing free radical damage and by absorbing damaging blue light rays. Because the eyes are subjected to such a high degree of oxidizing radiation each day, adequate dietary intake of lutein is a crucial component of providing optimal protection to the delicate tissues of the eye (lutein is only obtained through the diet, while zeaxanthin can be produced by conversion from lutein in the eye).
There are no known adverse side effects associated with dietary supplements containing lutein or zeaxanthin when used at recommended levels. Most supplements should be taken with a meal to lessen he chance of causing stomach upset and to increase their digestion and absorption (bioavailability).
Value
Dietary supplements containing lutein and zeaxanthin are available from a number of manufacturers as an alternative for those people not able or willing to increase their vegetable consumption. When choosing a supplement, be sure to select one that delivers an effective level of lutein (about 6mg per day). Lutein is now being added to national vitamin brands such as Centrum. Unfortunately, the Centrum brand provides only 250 micrograms (mcg) of lutein or about 24 times less than the levels shown to be effective in preventing ARMD.
Dosage
From studies of ARMD rates and dietary intake, it appears that diets providing about 6 milligrams (mg) of lutein per day can reduce ARMD prevalence by nearly half. Eating more of the carotenoid-rich foods mentioned above should be your first step to increase lutein intake. Unfortunately, recent diet surveys have indicated that consumption of these foods has dropped more than 20% in the two groups at highest risk for ARMD (women and elderly). As many carotenoids are rapidly cleared from the body, you may also want to consider splitting your daily intake into two doses (3mg with breakfast and 3mg with dinner).
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