Research on AMD and diet focuses on both preventing and slowing the progression of the disease. Two recently published European studies of over 5,000 people found
that those who ate a Mediterranean-style diet had a lower risk of developing AMD. The diets shown to be protective focused on vegetables, fruits, whole grains, legumes, fish, poultry and plant-based oils.
People adhering to this eating pattern had a greater intake of carotenoids, such as lutein and zeaxanthin. These phytochemicals help to absorb harmful blue light that may accumulate and damage the retina of the eye. The best sources of lutein and zeaxanthin are dark green leafy vegetables, such as kale, spinach and other greens. From these studies and others, it is generally agreed that for prevention of AMD a healthful diet, not dietary supplements, offers good protection.
That said, why are there so many dietary supplements marketed for eye health? In general, these products are designed for the large population of Americans with existing AMD. Many product formulations are based on results of significant studies conducted on supplement use and the progression of AMD. Two major studies are often cited.
A large study conducted by the National Institutes of Health called the Age-Related Eye Disease Study (AREDS) in 2001 looked at the effects of a combination of carotenoids and specific vitamins and minerals on the risk of cataracts and advanced AMD. A subsequent study published in 2013, the AREDS2, varied the original supplement formula and checked for results. The studies were conducted on subjects who had known AMD, exploring what mix of dietary supplements were best for reducing the risk of progressing to a more advanced stage.
From the AREDS studies, supplements were found to be helpful in delaying the progression of AMD. Specifically, the following nutrients were clinically effective when taken in these doses daily: vitamin C (500 mg), vitamin E (400 IU), lutein (10 mg), zeaxanthin (2 mg), zinc as zinc oxide (25 mg) and copper as cupric oxide (2 mg). The copper included in the supplements is necessary because of decreased absorption of copper when large levels of zinc are ingested. Of note, formulas that contained omega-3 fatty acids were not shown to provide any eye health benefit.
At some point, we each need to make personal health decisions regarding the use of dietary supplements. Keeping in mind the nutrients found to be effective in preventing AMD progression, I planned the following menu and analyzed it. Included were foods I know to contain ample vitamin C, vitamin E, zinc, and carotenoids, throwing in omega-3 fatty acid sources as well.
Breakfast: 1 scrambled egg with ¼ cup sautéed green pepper and 1 green onion; 1 slice rye toast; 1 small orange; 1 cup reduced-fat milk.
Lunch: Spinach salad made with 1½ cups raw spinach, 1 tablespoon sunflower seeds, ½ cup sliced strawberries, 3 ounces grilled salmon and 2 tablespoons vinaigrette salad dressing; 6 whole-grain crackers; beverage of choice.
Dinner: 3 ounces baked pork tenderloin; ¾ cup brown rice; 1 cup steamed broccoli and carrots; 1 whole-grain dinner roll; ¾ cup blueberries topped with ½ cup plain low-fat yogurt and ½ teaspoon honey; beverage of choice.
Snack: ¼ cup almonds; 2 dried apricots.
From my analysis, while this menu easily meets the recommended dietary allowance guidelines for important eye health nutrients, I could not achieve the amounts seen in the AREDS studies. It would be hard to get levels of these nutrients from food intake alone.
Thus, my general nutrition advice for eye health from a registered dietitian nutritionist: Throughout your life, eat a varied diet with ample servings of fruits, vegetables, fish, whole grains, nuts and seeds.
Shield your eyes from exposure to sunlight, avoid tobacco and get regular physical activity to further protect your eyes. Get your eyes examined every two years, or as directed by your eye doctor, for signs of age-related eye diseases.
In the event you are diagnosed with AMD, consult with your eye care provider and consider taking dietary supplements that adhere to the AREDS studies.
Sara Perovich is a Registered Dietitian Nutritionist working as a clinical dietitian in the Albuquerque area. She is a member of the New Mexico Academy of Nutrition and Dietetics.