There’s good evidence that certain dietary supplements—including antioxidant vitamins, zinc, and copper—may slow the advance of age-related macular degeneration (AMD). But what about getting those nutrients the natural way—from a healthy diet?
The widely accepted model for healthy eating is the Mediterranean diet, which abounds in fruit, vegetables, whole grains, nuts, legumes, and fish, with only modest amounts of red and processed meats. This largely plant-based diet is naturally rich in antioxidants and healthy fats, including the same nutrients found in dietary supplements designed to slow AMD.
Findings published in 2015 in The American Journal of Clinical Nutrition offer encouraging evidence that following a Mediterranean eating plan may offer even more protection than those supplements.
Diet vs. supplements
Researchers at Tufts Medical Center and Harvard Medical School looked at data from 2,525 volunteers with intermediate AMD who participated in the Age-Related Eye Disease Study (AREDS). Among them, 1,028 went on to develop advanced AMD over a 13-year period.
Using dietary questionnaires completed by the volunteers, researchers scored the participants on how closely they adhered to the Mediterranean diet. The scoring system covered nine component food groups: vegetables, fruits, legumes, whole grains, nuts, fish, red and processed meats, alcohol, and the ratio of monounsaturated fats to saturated fats.
Volunteers who consumed generous amounts of foods considered to be healthy—nuts, fruits, vegetables, and whole grains, for instance—were awarded one point for each food group. They also received points if they consumed only modest amounts of foods considered to be unhealthy, such as red and processed meats. Participants received one point if they consumed moderate amounts of alcohol (the equivalent of one glass a day for women, two glasses a day for men).
The higher the Mediterranean score, the researchers found, the less likely people in the study were to develop AMD. Subjects with the highest scores had a 26 percent lower risk of progressing to advanced AMD over the course of the study.
In one sense, that finding isn’t surprising. A high Mediterranean score, the researchers showed, was associated with higher intake of beta-carotene, vitamins C and E, and other nutrients that may be associated with healthier vision.
But the study also suggests that eating a healthy diet is even more important than popping a supplement. Subjects in the study who followed the Mediterranean diet had a lower risk of advanced AMD compared with individuals taking an eye-related dietary supplement.
Caffeine may help
In addition, the Coimbra [Portugal] Eye Study, in an update presented at the 2016 annual meeting of the American Academy of Ophthalmology, suggests a protective effect associated with high adherence to the Mediterranean diet through an increased consumption of fruits.
The study’s micronutrient analysis showed a possible protective effect associated with increased consumption of caffeine—something not previously reported—as well as dietary fibers, beta-carotene, and vitamins C and E.
It’s important to note that these are preliminary findings that were presented at a conference and have not yet undergone the rigorous peer-review process required before a study’s publication to ensure it meets established scientific standards.
How can a healthy diet protect your eyes? There are probably several ways, according to the experts.
• The plant-based Mediterranean diet abounds in antioxidants and other substances that can decrease inflammation in the body—and both oxidative stress and inflammation are part of the process that leads to AMD.
• Another risk factor for AMD is high blood pressure, and research shows that eating patterns like the Mediterranean diet—rich in fruits, vegetables, whole grains, and nuts—can help keep your blood pressure in check.
• Obesity is still another possible risk factor for AMD. And while there’s no magic bullet for healthy weight, following a Mediterranean diet has been shown to help some people shed pounds and keep them off.
It’s worth noting that not everyone in the AREDS study benefited equally from a Mediterranean diet. Participants with a particular genetic profile, one dubbed CFH Y402H, linked to a lower risk of AMD, got a bigger benefit than those with a high-risk genetic profile—a reminder that the genes you inherit play a significant role in your health profile. But even if a healthy diet alone won’t prevent AMD, it may help slow the process.
Most researchers agree that following an eating plan like the Mediterranean diet is healthy for other reasons. A 2013 study by Spanish researchers, published in BMC Ophthalmology, showed that a diet loaded with fruits and vegetables containing vitamins C and E—a hallmark of the Mediterranean diet—significantly reduced the risk of cataracts.
Other research has shown that the Mediterranean diet is associated with a lower risk of heart disease, stroke, and diabetes.
Read more about preventing age-related macular degeneration.
Peter Jaret is the author of several health-related books, including “In Self-Defense: The Human Immune System” (Harcourt Brace), “Nurse: A World of Care” (Emory University Press), and “Impact: On the Frontlines of Public Health” (National Geographic). A frequent contributor to National Geographic, The New York Times, Reader’s Digest, Health, More, AARP Bulletin, and dozens of other periodicals, Jaret is the recipient of an American Medical Association award for journalism and two James Beard awards. He lives in Petaluma, Calif.