New Lutein, Zeaxanthin and Omega-3 Research
Lutein & Zeaxanthin Lower Cataract Risk
Lutein and zeaxanthin are believed to help protect the eye’s lens against cataract formation, but findings from epidemiologic studies haven’t always been consistent.
To shed more light on the relationship between these two carotenoids and age-related cataract, researchers conducted a meta-analysis1. This analysis combined the results of six separate high-quality population-health studies involving 42,000 participants.
The study found that participants eating the highest amount of lutein and zeaxanthin would expect to have a 25% lower risk of nuclear cataract (a clouding of the central part of the lens).
The researchers also observed a dose-response relationship: Compared with low intakes, the risk for nuclear cataract went down as consumption went up. Specifically, for every 300 micrograms (1/3 of a milligram) of additional lutein intake daily, the risk of nuclear cataract declined by 3%.
The finding is important because intake of lutein / zeaxanthin is estimated to be 2 milligrams daily in the US, while about 6 milligrams a day has been linked to cataract risk reduction.
The meta-analysis findings echo the results of the Age-Related Eye Disease Study 2 (AREDS2). In AREDS2, participants with the poorest intake of dietary lutein and zeaxanthin were 32% less likely to progress to a level of cataract requiring surgery. A 36% reduction in the development of any severe cataract was seen in AREDS2 as well.
While AREDS2 didn’t look at different types of cataract, the meta-analysis did. The researchers found that the risk for other types of cataract – cortical and posterior sub-capsular (cataracts on the edge of or at the back of the lens) were 15% and 23% lower in people who ate higher levels of lutein and zeaxanthin, but a clear-cut dose-response was not seen for these cataract types.
Carotenoids & Omega-3 in Early AMD
A recent article2 by Tufts University researchers provided an overview of lutein and zeaxanthin in early AMD. While calling for more research, the authors conclude that lutein and zeaxanthin appear to diminish the development or progression of early AMD. The results of a new study bolster the article’s conclusion.
In this trial, researchers measured the density of macular pigment in people with early AMD who received either lutein (12 mg), zeaxanthin (0.6 mg) and the omega-3 fat DHA (280 mg) daily or a placebo.
Early AMD is diagnosed by the presence of yellow-white spots called drusen in the macula. About 14% of people with the early stage of this disease will go on to develop late AMD over time.
Lutein and zeaxanthin are protective pigments concentrated in the macula. DHA was included with the carotenoids because it’s thought to increase the transport of lutein and zeaxanthin to the retina, where it’s also involved in retinal function.
One year later, the patients getting the carotenoid and omega-3 combination had a significant increase in macular pigment density compared to the placebo-treated group. Some evidence suggests that increasing macular pigment density is related to the risk of developing AMD.
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