May 2000 May 2000
Spinach Keeps Eyes Strong To the Finish
Lynda Zimmerman, zimmermanl@missouri.eduMany older adults develop an eye problem that seriously impairs their vision. The good news, however, is that losing your eyesight doesn't have to be an inevitable part of aging.
There is increasing evidence that what you eat can make a big difference in the long-term health of your eyes -- in addition to not smoking, wearing sunglasses, and having regular eye exams.
Cataracts and Macular Degeneration. The two most common age-related vision problems are cataracts and macular degeneration.
Cataracts occur when the lens of the eye becomes cloudy, resulting in a gradual loss of vision. Worldwide, cataracts rank as the number one cause of blindness.
The second problem, age-related macular degeneration (ARMD) is less well known, but is the leading cause of irreversible blindness among Americans over 65. ARMD occurs when macular cells in the center of the retina deteriorate.
Both disorders are caused, in part, by oxidative damage from environmental stress (sunlight, pollution, and smoking), as well as the body’s own metabolism. It’s an inevitable consequence of living. When the stress is greater than the body’s ability to fight it, the resulting cell damage is thought to lead to chronic conditions of aging, including cataracts, macular degeneration, heart disease, and cancer.
Carotenoids protect eyes. Research shows that dark green leafy vegetables -- especially spinach, collard or turnip greens, and kale -- may protect eyesight.
Lutein and zeaxanthin in these vegetables are thought to be the protective elements. These pigments are found in concentrated amounts in the retina and protect eyes in two ways. First, they filter out the most damaging portion of the UV spectrum -- blue light. Second, they act as antioxidants, which protect against the oxidation of lipids in the eye.
Studies have shown there are low levels of these two nutrients in the retinas of people with both ARMD and cataracts. In addition, people with eye disease typically have low intakes of foods rich in lutein and zeaxanthin.
Researchers believe that these antioxicant nutrients may not only help prevent eye disease from occurring, but may help stop further deterioration of existing conditions. So it's never too late to start making changes, even if some eye damage has already occurred.
While spinach, kale, and collard or turnip greens contain the largest amounts of lutein and zeaxanthin, other fruits and vegetables are also fairly good sources: corn, broccoli, Romaine lettuce, zucchini, green peas, Brussels sprouts, oranges, kiwi, red seedless grapes, papayas, and tangerines. Your best bet is to eat these foods three to four times each week, as well as a variety of other produce, with a goal of five or more total servings every day.
Many older adults develop an eye problem that seriously impairs their vision. The good news, however, is that losing your eyesight doesn't have to be an inevitable part of aging.
There is increasing evidence that what you eat can make a big difference in the long-term health of your eyes -- in addition to not smoking, wearing sunglasses, and having regular eye exams.
Cataracts and Macular Degeneration. The two most common age-related vision problems are cataracts and macular degeneration.
Cataracts occur when the lens of the eye becomes cloudy, resulting in a gradual loss of vision. Worldwide, cataracts rank as the number one cause of blindness.
The second problem, age-related macular degeneration (ARMD) is less well known, but is the leading cause of irreversible blindness among Americans over 65. ARMD occurs when macular cells in the center of the retina deteriorate.
Both disorders are caused, in part, by oxidative damage from environmental stress (sunlight, pollution, and smoking), as well as the body’s own metabolism. It’s an inevitable consequence of living. When the stress is greater than the body’s ability to fight it, the resulting cell damage is thought to lead to chronic conditions of aging, including cataracts, macular degeneration, heart disease, and cancer.
Carotenoids protect eyes. Research shows that dark green leafy vegetables -- especially spinach, collard or turnip greens, and kale -- may protect eyesight.
Lutein and zeaxanthin in these vegetables are thought to be the protective elements. These pigments are found in concentrated amounts in the retina and protect eyes in two ways. First, they filter out the most damaging portion of the UV spectrum -- blue light. Second, they act as antioxidants, which protect against the oxidation of lipids in the eye.
Studies have shown there are low levels of these two nutrients in the retinas of people with both ARMD and cataracts. In addition, people with eye disease typically have low intakes of foods rich in lutein and zeaxanthin.
Researchers believe that these antioxicant nutrients may not only help prevent eye disease from occurring, but may help stop further deterioration of existing conditions. So it's never too late to start making changes, even if some eye damage has already occurred.
While spinach, kale, and collard or turnip greens contain the largest amounts of lutein and zeaxanthin, other fruits and vegetables are also fairly good sources: corn, broccoli, Romaine lettuce, zucchini, green peas, Brussels sprouts, oranges, kiwi, red seedless grapes, papayas, and tangerines. Your best bet is to eat these foods three to four times each week, as well as a variety of other produce, with a goal of five or more total servings every day.
Other important antioxidants. Vitamins C and E also show promise in protecting eyesight. These nutrients guard against oxidative stress and may even help repair the damage.
High concentrations of vitamin C are normally found in the lens of the eye, but as you age the amount decreases. Moreover, blood levels of vitamin C are low in people with cataracts. Getting more C could help replenish eye stores of the vitamin and prevent cataracts from forming, although this theory is not yet proven. Some researchers speculate that vitamin C's role may be an indirect one. It's known to help vitmain E be a more effective antioxidant and may similarly aid carotenoids, freeing them to do their eye-saving work.
Similarly, studies have shown high blood levels of vitamin E were linked to a lower incidence of cataracts and that people taking vitamin E supplements cut their risk of cataracts in half. Other studies, however, have not found as much benefit.
A joint panel of the American College of Clinical Gerontology and the American Aging Association recommend adults over the age of 65 strive for 200 milligrams of vitamin C a day, the amount in about five servings of fruits and vegetables. Good sources of C are citrus fruits, strawberries, papaya, broccoli, tomatoes, peppers, and potatoes. The panel recommends 200 IU of vitamin E a day. Food sources of E include vegetable oils, wheat germ, nuts, and seeds. Most people, however, are unable to obtain the recommended amounts without supplements. (High doses of vitamin E should not be taken with blood-thinning medications, aspirin and some herbs; check with your physician.)
The bottom line. Although researchers don't have all the answers regarding the role of antioxidants in preventing age-related eye problems, the odds are good that eating more fruits and vegetables will help. An added bonus: with increasing evidence of the preventive power of fruits and vegetables for many other diseases, such a menu probably helps preserve more than your eyesight.
Sources: Environmental Nutrition, September 1999; Food & Fitness Advisor, October 1999; Environmental Nutrition, August 1999.
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