As we age, a lifetime of wear and tear takes a toll on our eyes. Two common vision problems that come with aging are cataracts and macular degeneration. Cataracts are particularly common in people over the age 75 and macular degeneration is the leading cause of blindness in older Americans.
The good news is that, while these conditions may be a natural part of aging, researchers have identified factors that can help delay their onset. These include not smoking, limiting your exposure to sun, taking vitamin E supplements and making sure you eat plenty of fruits and vegetables high in vitamin C and the carotenoids, which include lutein and zeaxanthin.
You’ve probably heard several of these recommendations before, but why lutein and zeaxanthin? These are pigments found in concentrated amounts in the retina. They help protect the eyes by filtering out blue light, the most damaging portion of the UV spectrum. They also act as antioxidants, scavenging free radicals and protecting the eye against damage caused by sunlight and lipid oxidation.
Lutein and zeaxanthin are found in a variety of foods, particularly winter squash, corn and dark green, leafy vegetables like kale, spinach, broccoli and collard greens. They are responsible for the yellow color of corn and winter squash and help make dark green, leafy vegetables green. They’re also found in egg yolks.
Several studies in recent years have found a connection between consumption of foods rich in lutein and zeaxanthin and reduced risk of developing age-related cataracts and macular degeneration. In one study completed at Harvard University, those who ate greens and other lutein- and zeaxanthin-rich foods two to four times per week were only about half as likely to end up with macular degeneration as those who ate them less than once per month. In the other study, eating at least three servings weekly of dark green vegetables was protective against cataracts.
Lutein and zeaxanthin are not the only dietary components protective against eye degeneration. Two other, better known antioxidants, vitamins E and C, also are protective. A number of studies have shown that taking supplemental vitamin E can help lower the risk of cataracts. A supplement containing 200 I.U. of vitamin E per day seems to be the most efficacious. The role of vitamin C in protecting against cataracts is less well understood. Some speculate that it acts by stimulating the antioxidant action of vitamin E, lutein and zeaxanthin.
What if you’ve avoided dark green and yellow vegetables all your life? Is it too late to play catch-up? Cataracts and age-related macular degeneration do occur over time; however, many researchers believe that antioxidant nutrients not only can help prevent eye diseases but may help prevent further deterioration of existing conditions. Whatever your age, eating your veggies is always a good idea.
by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension