Consuming a Mediterranean-style diet, already linked to benefits for your heart and brain, might also help protect against the leading cause of blindness in older Americans. A recent study reports that at-risk patients whose diets scored highest on a Mediterranean-diet index were 26% less likely to progress to advanced age-related macular degeneration (AMD).
“Assessing overall diet with respect to ocular outcomes is relatively new in ophthalmic epidemiology,” noted Johanna Seddon, MD, of Tufts Medical Center, and colleagues in the American Journal of Clinical Nutrition, “and this study is the first, to our knowledge, to explore the association between [Mediterranean diet] score and progression to advanced AMD.”
FOODS AND PATTERNS: Dr. Seddon and colleagues analyzed data on 2,525 participants in the Age-Related Eye Disease Study (AREDS) who completed dietary questionnaires. Individual intakes of vegetables, fruit, legumes, whole grains, nuts, fish, red and processed meats, alcohol and monounsaturated versus saturated fats were then used to score participants from zero to nine for adherence to a Mediterranean-style diet. (See box.) Scores of six or higher were significantly associated with reduced risk of progression to advanced AMD. Among subjects with certain genetic risk factors, high Mediterranean diet scores were also associated with lower risk of incident advanced AMD.
Previous studies, the researchers noted, have linked high consumption of fish and fish oil, nuts, and lutein and zeaxanthin from vegetables with reduced risk of AMD. All are emphasized in the Mediterranean diet. On the other hand, consumption of red meat and trans fats – avoided in the Mediterranean diet – has been associated with elevated risk. In the Carotenoids Age-Related Eye Disease Study, following a Mediterranean diet was linked with a lower incidence of early AMD.
In the latest study, consistent with these prior findings, the protective association between diet and AMD progression was strongest for fish and vegetable consumption. But an overall Mediterranean dietary pattern was more strongly associated with reduced risk than consumption of individual food types.
The protective association between diet and AMD progression was seen regardless of whether patients were taking the AREDS antioxidant vitamin formula or a placebo.
MODIFYING RISK: “The biological basis for the documented health benefits of the Mediterranean diet score involves a decrease in oxidative stress and inflammation,” Dr. Seddon and colleagues observed. Both oxidative stress and inflammation play roles in AMD, so this may also explain the apparent protective benefit.
Keep in mind, however, that this is only the first study of its kind. As an observational study, it can’t prove cause and effect, and other factors can’t be excluded in explaining the apparent benefit of eating a Mediterranean-style diet.
TO LEARN MORE: American Journal of Clinical Nutrition, November 2015 —