New research published this month shows that fewer older Americans are developing macular degeneration — a major cause of vision loss and even blindness in older men and women. And the study suggests that a healthier diet — including leafy green vegetables and fish — could be one of the factors responsible for the decrease — from 9.4 percent to 6.5 percent — in the prevalence of the disease among people over age 40.
The study in the journal The Archives of Ophthalmology was just the latest in a growing body of research linking diet to eye health and the prevention of some troubling eye conditions.
Steven Pratt, M.D., the author of SuperHealth, says foods can help defend against not only macular degeneration but also a number of vision disorders including cataracts, which is a clouding of the lens that distorts vision, and glaucoma, an eye condition in which excessive fluid in the eyeball creates pressure that damages the optic nerve.
The antioxidants and nutrients that are linked to a lower risk of these eye ailments include lutein, omega-3 fatty acids, and vitamins C and E.
Here are the foods — rich in these protective substances — that appear to make the difference when it comes to eye health.
"Spinach is the king of the green leafies," says Pratt. But other good greens include kale and Swiss chard, plus turnip, mustard and collard greens. These leafy greens are excellent for the eye because they're rich in lutein, a carotenoid compound that is found in colorful fruits and vegetables and that protect cells from damage. A diet rich in spinach helps shield your macula — the center of the retina — from cell damage that can cause both age-related macular degeneration and cataracts. Certainly, if you have macular degeneration already, you want a lot of spinach in your diet — and if you have a family history of the disease, you should be loading up on that vegetable.
Cold-water fish like salmon, sardines, herring, mackerel and albacore tuna are the best fish to eat for the health of the back of the eye. DHA (docosahexaenoic acid) is the primary omega-3 fatty acid found in these fish. It's a nutrient that concentrates in the retina and may prevent plaque — which causes macular degeneration — from forming there. Boosting your DHA by eating four 3.5- to 4-ounce servings of cold-water fish weekly is a wonderful way to help prevent eye disease, Pratt says.
Sign up for the AARP Health Newsletter.
Indeed, a Johns Hopkins study published in the journal Ophthalmology in December reported that eating fish and shellfish that are rich in omega-3 seems to protect against advanced-age-related macular degeneration, even in those who smoked or were overweight — both risk factors for the disease. Cold-water fish also may help prevent retinopathy — damage to the retina — including blindness caused by complications from diabetes.
Walnuts are the best nut source of omega-3s. Pistachios are a close second. In small amounts they can be converted to EPA (eicosapentaenoic acid), another omega-3 fatty acid used by the eye, along with DHA. They are full of antioxidants and vitamin E, which work to combat inflammation and preserve cardiovascular health. What's more, walnuts help to lower C-reactive protein, a marker that signals there is inflammation in the body. Having a handful of walnuts a day can cut your risk of a cardiac event by as much as 50 percent, according to several large research projects, including the ongoing Nurses Health Study. (Other types of nuts, including almonds, hazelnuts, pecans and peanuts, can also provide the same heart benefit, according to the Food and Drug Administration.)
Blueberries, blackberries, strawberries, mulberries, cherries and even grapes are outstanding foods for protecting cardiovascular health, which makes them stars for eye health, too. They're great for lowering both inflammation and blood pressure. And high blood pressure is a risk factor for macular degeneration. Blueberries and blackberries also contain anthocyanins, which have the dark purple pigments that fight inflammation and improve blood flow. They also help prevent blockages to the arteries that feed oxygen to the retina, says Christine Gerbstadt, M.D., spokesperson for the American Dietetic Association and author of Doctor's Detox Diet: The Ultimate Weight Loss Prescription.
5. Orange bell peppers
These peppers are the best dietary source of zeaxanthin, the other carotenoid that concentrates in the back of the eye. The higher the level of carotenoids like lutein and zeaxanthin, the lower the risk for cataracts and macular degeneration. Orange bell peppers have a lot of vitamin C and more zeaxanthin per mouthful than any food on the planet, Pratt says. Other orange foods — including gogi berries, pumpkin, squash, sweet potatoes and carrots — may have similar benefits. These orange-colored choices also are chock-full of vitamin A, which boosts night vision. And they contain a carotene that helps lower the risk of cataracts.
Broccoli activates anti-inflammatory enzymes in the body and acts to encourage detoxification. Other vegetables like Brussels sprouts and cabbage rev up these enzymes. Broccoli also triggers anti-inflammatory systems that help decrease inflammation in the back of the eye.
Green tea, black tea and oolong tea are best for preventing cataracts. Teas may help prevent macular degeneration, too, by preventing the growth of new blood vessels in the back of the eye, Pratt says. When too many new blood vessels grow beneath the retina, they leak blood and fluid. This leakage causes permanent damage and results in blind spots and serious loss of vision from "wet" macular degeneration.
New research shows that soy — especially soy milk, soy sauce, miso and tempeh — are rich in isoflavones, compounds with powerful antioxidant properties that protect against cataract formation in animals. Isoflavones also may help restore tear production that's been reduced by dry eye syndrome, according to a 2010 study.
Eggs contain the omega-3 fatty acid DHA and are the most readily available source of lutein and zeaxanthin. An egg per day for most people, unless you have diabetes, is excellent eye food. Diabetics need to ask their doctor whether eggs can be a part of their diet.
Avocados are one the most nutrient-rich fruits we eat, so it's no wonder they're great for eyes. They contain lutein and help prevent macular degeneration and cataracts. "They're also a great source of other important eye nutrients such as beta-carotene, vitamin C, vitamin B6 and vitamin E," Gerbstadt says. Those vitamins place avocados among the top-10 eye foods.
Jennifer Nelson is a Florida-based writer who also writes for Glamour, MSNBC and WebMD.
Remember to go to the AARP home page every day for tips on keeping healthy and sharp, and great deals.