New research shows that eggs are a highly bioavailable source of lutein, a carotenoid important for eye and skin health.
"Studies indicate that lutein can help protect against diseases such as age-related macular degeneration (AMD) and cataracts, as well as lowering risk for some forms of cancer and heart disease," said Elizabeth J. Johnson, Ph.D., the study's lead author. The study published in the August 2004 issue of the Journal of Nutrition compared the bioavailability of lutein from various sources, in order to determine how it can impact dietary recommendations. Highly bioavailable forms of nutrients are those that the body can most easily absorb and utilize.
Researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University provided participants with either a lutein supplement, a lutein ester supplement, spinach or lutein-enriched eggs, in random order. Each source of lutein provided the participants with approximately 6 milligrams (mg) lutein per day. Dr. Johnson and colleagues collected blood samples from fasting participants 2 weeks prior to the study, to determine basal levels of carotenoids, and before and after each 9 day test phase to analyze changes in lutein concentration.
Results indicated a significantly greater blood lutein response with egg consumption compared to the other lutein sources studied. Specifically, participants' lutein blood levels were approximately three times higher after eating eggs. Dr. Johnson stated it is possible that "lutein from eggs is more readily absorbed into the bloodstream than lutein from other sources because of components in the egg's yolk, such as lecithin."
Previous studies have shown that egg intake increases blood lutein levels and these data further reiterate the importance of eggs in one's diet. Dr. Blumberg at Tufts University says, "One egg yolk provides approximately 200 micrograms of lutein, and lutein in eggs is 200-300 percent more bioavailable than vegetable sources of lutein." Eggs provide lutein in a lipid form, which is easier for the body to absorb. This high bioavailability provides individuals with more biological benefits at a lower intake of lutein, making it easier to consume what is thought to be a healthy intake of lutein. This study's results, along with previous research, demonstrate that eggs are an excellent, inexpensive source of many beneficial nutrients including this important carotenoid.