Your mother was right when she told you to "eat your spinach; it's good for your eyes." She may have even told you that it is the vitamin A (as beta-carotene) in spinach that's so good for you. She was right. But she didn't know that besides beta-carotene, spinach contains lutein, another very important carotenoid for eye health.
Recent research has shown that lutein is a major eye pigment in the retina. Lutein is especially concentrated in the rods, the visual cells of the retina responsible for black and white vision in the dark.
Lutein is a potent antioxidant and researchers believe that the retina requires it for protection from the damaging effects of light and oxygen.
Both light and oxygen can create free radicals that play havoc with the abundant lipids in the membranes of the visual cells. Experts believe that the uncontrolled generation of free radicals in the eyes can ultimately lead to macular degeneration and cataracts.
Apart from lutein, healthy eyes have an intricate antioxidant defense system to deal with free radical stress. Antioxidant enzymes, such as zinc-dependent superoxide dismutase and selenium-containing glutathione peroxidase are very active in the ocular lens. Glutathione peroxidase requires a steady supply of glutathione, yet studies show that ocular glutathione levels decline as we age. Free glutathione also protects the proteins in the lens from becoming insoluble and cloudy.
The lens is also rich in the natural antioxidants beta-carotene, vitamin E and vitamin C. Taurine, a sulfur amino acid, is abundant in all ocular tissues, where it may function as a membrane stabilizer, antioxidant, and neurotransmitter. Some flavonoids, such as anthocyanosides and proanthocyanidins, also appear to have antioxidant functions in the retina and the small capillary blood vessels that nourish the ocular tissues.
As you can see, a wide spectrum of antioxidant defense systems are involved in ocular health, and most of the factors that keep these systems operating have to come from your diet.
Seeing Well as You Grow Older. Growing older is a threat to our vision and eye health. Macular degeneration, or impaired central vision, afflicts 28% of men and women aged 75 to 85. Cataracts, cloudy areas on the lens that block light entering the eye, are a leading cause of blindness and the third most common chronic illness of people aged 60 and older.
There is no cure for the most common form of macular degeneration. Early detection is key to reducing further damage and loss of vision. Surgery is the only treatment for cataracts once vision is impaired. Thus, the focus of recent eye research has been on ways to delay the onset and reduce the risk of developing these disorders by protecting our vision.
Antioxidant Protection for the Eyes. Macular degeneration that occurs with age and development of cataracts may be related to free radical damage in the eye. One recent study found that people who consume plenty of fruits, vegetables, and other nutritious foods or take daily multiple vitamin supplements reduced their risk of developing cataracts by about 37%.
Experts agree that the critical protective nutrients are antioxidant substances like vitamins A, E and C which counteract the damaging effects of oxygen. Just as oxygen rusts iron, it can also damage cell membranes and other proteins in the lens of the eye. Oxidative damage can occur through exposure to sunlight, cigarette smoke, or other environmental toxins. Antioxidant nutrients are thought to prevent this destruction by converting oxygen compounds to less harmful forms.
What Can You Do Now to Protect Your Eyesight? Although numerous studies agree that poor nutrition is associated with a higher risk of developing cataracts, further research is needed to identify more precisely how antioxidants may act as a protective shield. And, a better diet and vitamin supplements aren't automatic protection. Cataracts and other eye damage are caused by many factors. Environmental exposure to sunlight and certain diseases like diabetes are also related.
Even though no one knows exactly how much of each nutrient may be needed to preserve vision, here are some general sound guidelines you may wish to follow:
Have your eyes checked regularly for signs of eye problems. Many people do not realize they have a problem until their vision becomes impaired.
Wear protective sunglasses regularly while out of doors. Lenses which reduce exposure to sunlight or artificial light of 300 to 400 nm wavelengths are recommended.
Avoid overconsumption of calories leading to weight gain as a means to lower risk for diabetes. Diabetics are 3 to 4 times more likely to develop cataracts.
Eat a nutritious diet that includes a wide variety of fruits and vegetables.
Check with your doctor to see if taking supplements or antioxidant vitamins and minerals may be advisable for you.