By Victoria Shanta Retelny, R.D.
Those brightly dyed Easter eggs look pretty—and may help you see better, too, suggests new research in the Journal of Nutrition. Egg yolks contain lutein and zeaxanthin, carotenoid compounds that mounting research links with reduced risk for age-related macular degeneration (AMD). Characterized by the deterioration of the central retina, or macula, AMD is the leading cause of blindness in people over 50.
Green and yellow vegetables, including spinach and corn, are also rich in lutein and zeaxanthin. Hens absorb the carotenoids from their feed (often corn) and the nutrients concentrate in their eggs’ yolks. From vegetables and eggs, we, in turn, absorb these compounds. Some deposit in our eyes, where they are referred to as “macular pigment.”
“Macular pigment appears to protect the retina by absorbing potentially harmful wavelengths of light, and by quenching free radicals that can damage tissues,” says Adam Wenzel, Ph.D., who conducted the recently published research at the University of New Hampshire. While previous research has shown that eating spinach increases macular pigment density (presumably boosting protection against AMD), scientists had never studied whether eating eggs—which contain only a fraction of the carotenoids found in vegetables—might have a similar effect.
To find out, Wenzel and his colleagues (partly funded by the American Egg Board) randomly assigned 24 women to consume six eggs per week or a placebo pill daily. After 12 weeks, macular pigment density had increased in the women eating eggs but not in those taking the placebo. “This suggests that the relatively low concentration of carotenoids in egg yolks may be highly bioavailable to the retina,” says Wenzel, explaining that the fatty yolk is a perfect delivery vehicle for fat-soluble carotenoids.
But how do those fatty yolks affect cholesterol? In otherwise healthy people, they don’t, according to Wenzel’s research and another study in the journal, which found that eating an egg daily for five weeks boosted levels of lutein and zeaxanthin, but did not significantly impact cholesterol or triglyceride levels.
Bottom line: “Our data show that eating an egg a day isn’t a factor for raising cholesterol,” says Robert Nicolosi, Ph.D., one of the study’s authors and director of the Center for Health & Disease Prevention at the University of Massachusetts, Lowell. “In fact, people who avoid eggs may be missing an opportunity to consume vital nutrients that can help prevent age-related macular degeneration.”