Eggs for Eye Health

Two recent studies from the University of Massachusetts suggest that eating one egg a day could reduce the risk of developing age-related macular degeneration (AMD).

Egg yolks are a rich source of lutein and zeaxanthin, two carotenoids that accumulate in the macular pigment of the retina and are associated with a reduced incidence of AMD, the No. 1 cause of vision loss and legal blindness in adults over 60 in the United States.

AMD is a progressive eye condition that ultimately destroys the central vision necessary for reading, driving, identifying faces, watching television, doing fine detailed work, navigating stairs and performing other daily tasks.

The objective of the first study, by Elizabeth Goodrow et al., was to investigate the effect of consuming one egg per day for five weeks on the serum concentrations of lutein, zeaxanthin, lipids and lipoprotein cholesterol in individuals over 60 years of age. The 18-week study included one run-in and one washout period of no eggs prior to and between two 5-week interventions of either consuming one egg or egg substitute per day. In the 33 participants, serum lutein and zeaxanthin concentrations increased 26% and 38%, respectively, after 5 weeks of one egg per day, compared with the phase prior to consuming eggs. Serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were not affected.

The objective of the second study, by Adam J. Wenzel et al., was to determine whether increased consumption of eggs would increase retinal lutein and zeaxanthin, or macular pigment optical density (MPOD). Twenty-four females were assigned to a pill treatment, or one of two egg treatments for 12 weeks. Those in the pill treatment group consumed one sugar-filled capsule per day. The women in the egg treatment group consumed six eggs per week, containing either 330 micrograms or 965 micrograms of lutein and zeaxanthin per yolk. Serum zeaxanthin and MPOD, but not lutein, increased in both egg treatment groups. Serum cholesterol concentrations did not change in either egg treatment group, but total cholesterol and triglycerides increased in the pill treatment group.

Both studies are published in the Oct. 2006 issue of Journal of Nutrition.