Dec. 27, 2005 -- A healthy diet may be a feast for aging eyes.
The study by Redmer van Leeuwen, MD, PhD, and colleagues appears in The Journal of the American Medical Association.
AMD is the most common cause of irreversible blindness in developed countries, writes van Leeuwen, who works at Erasmus Medical Centre in the Netherlands.
AMD affects the macula, located in the center of the retina. In the late stages of AMD, people can't read, recognize faces, drive, or move freely, the researchers write.
They note that AMD becomes much more common with age, and that one in 10 white adults age 80 and older has late-stage AMD.
The Dutch scientists studied more than 4,100 healthy older adults in a middle-class suburb of Rotterdam in the Netherlands.
The study started in the early 1990s. Back then, none of the participants had AMD. All were at least 55 years old from a suburb of Rotterdam, the Netherlands.
Participants completed surveys about the foods they typically ate and any supplements they were taking. They were also interviewed by a dietitian.
The data were used to estimate participants' intake of various antioxidants. Antioxidants are compounds found naturally in a wide range of foods, including fruits, vegetables, and whole grains.
Participants' eyes were also screened every three or four years for AMD. They were followed for an average of eight years.
During that time, 560 were found to have AMD. Most had early stages of the disease.
Four antioxidants -- beta carotene, vitamin C, vitamin E, and zinc -- may have teamed up for better eye health.
People with above-average intakes of all four antioxidants were 35% less likely to develop AMD during the study.
Vitamin E and zinc stood out. Both were linked to lower odds of getting AMD. The more vitamin E or zinc people ate, the lower their risk of AMD, the study shows.
The researchers adjusted for other factors that might make AMD more likely.
Use of dietary supplements didn't affect AMD risk, for better or worse, according to van Leeuwen and colleagues.
They admit that they don't have AMD totally figured out, and that participants' self-reported eating habits may not have been perfectly accurate.
Still, the researchers write that their study "suggests that the risk of AMD can be modified by diet; in particular, by dietary vitamin E and zinc."
The Dutch team calls for additional studies to check their findings. Meanwhile, they mention these food sources of the antioxidants they studied:
- Vitamin E: whole grains, vegetable oil, eggs, nuts
- Zinc: Meat, poultry, fish, whole grains, dairy products
- Beta carotene: Carrots, kale, spinach
- Vitamin C: Citrus fruits and juices, green peppers, broccoli, and potatoes
How much of which foods did participants eat? Did they drink orange juice every day, munch on nuts at happy hour, and serve up salads of carrots and dark, leafy greens with a side of broccoli?
The breakdown of who ate what isn't included in the study. It's also not known if participants had followed those diet habits for a little while or a lifetime.