The thought of aging usually makes us worry about chronic diseases, such as heart disease, cancer, and diabetes—not eye health. Yet, there is a growing prevalence of age-related eye diseases, bringing the whole issue of vision and eye health more into focus. There is also a growing body of research pointing to a simple dietary prescription as a potential way to prevent vision loss.
It makes sense—the tissues of the eyes are susceptible to oxidative damage, just like tissues elsewhere in the body. And sunlight causes oxidative damage to the eye. Studies suggest that a diet rich in nutrients that have antioxidant and anti-inflammatory properties may help offset vision problems. That’s why experts believe that nutrition plays a vital role in eye health. “It’s very important, since it’s the only means available to noninvasively delay the progress of age-related eye disease at present,” says Allen Taylor, PhD, director of the Laboratory for Nutrition and Vision Research at Tufts University’s USDA Human Nutrition Research Center on Aging in Boston.
Here’s a look at some of the most common eye diseases that seem to accompany aging, and what science suggests we can do to head them off.
* Age-Related Macular Degeneration (AMD), the leading cause of vision loss in people 65 and older, affects more than 10 million Americans. It gradually breaks down the macula (the densest part of the retina that contains your photoreceptors), thereby destroying central vision, which is what allows you to see fine detail for tasks such as reading or driving.
Nutrition Links: The most revealing findings to date have been from the Age-Related Eye Disease Study (AREDS), a study of 4,519 adults ages 60-80. They indicated that a specific antioxidant plus zinc formula (with vitamin C, vitamin E, beta-carotene, and zinc) was effective at reducing AMD risk. In addition, Harvard researchers concluded that “a healthy lifestyle with a diet containing foods rich in antioxidants, particularly lutein and zeaxanthin, as well as omega-3 fatty acids, appears beneficial for AMD and possibly cataracts.” Lutein and zeaxanthin are two carotenoids that concentrate in the retina and lens, and one of their key protective functions seems to be helping to block out damaging UV radiation. The duo is found in egg yolks and dark-green leafy vegetables. For reducing the risk of cataracts and age-related macular degeneration, a 6-20 mg daily dose of lutein should be consumed through diet or supplements. Although there is not much information on the amount of zeaxanthin to consume, both lutein and zeaxanthin have been shown to be safe when taken in amounts higher than 10 mg for many months.
Other findings from a five-year study of more than 2,200 Australian older adults (average age of 64) suggest that consuming omega-3 fatty acids, namely eating three or more portions of oily fish per week, could reduce the risk of developing AMD by as much as 70 percent. Another study of 7,752 adults found that those with the highest vitamin D blood levels had a 40 percent reduction in the risk of AMD compared to those with the lowest concentrations. Omega-3 oils should provide 200-500 mg of DHA (docosahexaenoic acid) daily. It’s best to get your vitamin D levels checked first; a typical dosage is 2,000 to 5,000 IUs.
* Cataracts are a widespread condition, affecting nearly 20.5 million Americans age 40 and up. By age 80, more than half of all Americans have cataracts. Believed to be precipitated by lifetime UV light exposure, smoking, poor diet, and alcohol consumption, cataracts are a clouding of the lens that usually advances with age.
Nutrition Links: Glutathione is highly concentrated in the lens and is believed to act as a free radical scavenger that detoxifies the delicate tissue. Glutathione levels in the lens seem to drop as we age, which may make the lens increasingly vulnerable to damage. Glutathione is produced from N-acetlcysteine and vitamin C. Higher vitamin C intake in women under 60 years of age has been tied to a lower risk of cataracts, and using vitamin C supplements for 10 years or longer has been associated with a 60 percent risk reduction compared with no supplement use.
Besides vitamin C, a number of antioxidants have been studied for cataracts, but the evidence isn’t as compelling as it is for AMD. A few that seem promising so far include vitamin E, lutein and zeaxanthin, and multivitamin supplements, but more large-scale studies are needed to bolster the findings, says Taylor. Eyebright, an herb used since the Middle Ages to relieve inflammatory eye problems, has antioxidant properties that may protect the lens of the eye from damage.
* Glaucoma is one of the leading causes of blindness in the United States and the most common cause of blindness among African-Americans. Marked by damage to the eye’s optic nerve, which usually occurs due to increased fluid pressure inside the eye—called intraocular pressure (IOP)—it leads to vision loss and blindness.
Nutrition Links: Some older study findings have suggested that people who develop chronic, open-angle glaucoma (the most common type) may have a decreased ability to absorb thiamine, which may have an adverse effect on cells in the optic nerve. The RDA for thiamine is 1.4 mg daily, but most multiples have 50-100 mg. Chromium deficiency has also been observed in individuals with glaucoma. Aim for 200 mcg of chromium daily (the amount found in most multiples). Other studies suggest that both vitamin C and omega-3 fatty acid intake may reduce the risk of glaucoma by decreasing IOP. Take vitamin C in 500-mg doses two or three times daily.
* Diabetic retinopathy is a leading cause of blindness in the United States and in the industrialized world. It’s a complication of advanced or poorly controlled diabetes, which is caused by damage to the blood vessels of the retina, and it can lead to blindness. Generally, the longer a person has diabetes, say over 20 years, the more likely that person is to develop retinopathy. Advanced retinopathy affects about 1 in 20 people with diabetes. However, controlling blood glucose and blood pressure, and making lifestyle changes, has been shown to alter the rate of progression.
Nutrition Links: Lifestyle data from the Diabetes Control and Complications Trial, a study of more than 1,000 patients with type 1 diabetes, demonstrated that following a low-fat diet, as recommended by the American Diabetes Association, which includes keeping saturated fat intake to less than 10 percent of calories and total fat to less than 30 percent of calories, slowed the rate of retinopathy progression by 33.2 percent. Higher dietary fiber reduced it as well, whereas higher overall calorie intake, dietary fat, and cholesterol increased the risk.
Some preliminary animal trials suggest that a mere 2 percent increase in omega-3 fatty acid intake could cut disease severity in half. The omega-3 fatty acid DHA is highly concentrated in the retina. In addition, when researchers at the University of Wisconsin looked at antioxidants’ potentially protective effect, they found that users of vitamin C and E supplements (or multivitamin formulas with them) had a decreased risk of diabetic retinopathy; dietary intake of the same nutrients didn’t seem to have a preventive effect, which strongly suggests that Mom was right—take your vitamins!
What’s Right for Your Sight?
According to Marc Grossman, OD, author of Natural Eye Care, a variety of dietary nutrients and herbal supplements can help keep eyes healthy. The following are just some of the dietary daily dosage recommendations to help guard against AMD, cataracts, glaucoma, and diabetic retinopathy that you can find on Grossman’s website, naturaleyecare.com.
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SOLGAR BILBERRY GINKGO EYEBRIGHT COMPLEX Bilberry ensured sharp night vision for WWII pilots. This formula teams it with two other potent vision-sharpening nutrients in one convenient vegetarian capsule.
COUNTRY LIFE NATURAL BETA CAROTENE With 25,000 IU of vitamin A (beta carotene), key to staving off AMD, glaucoma and more, this is the clear choice for clear vision.Softgels are free of yeast, corn, wheat, and gluten.
NORDIC NATURALS OMEGA VISION combines a particularly concentrated form of omega-3 fish oil with key nutrients (including zeaxanthin) that research shows help protect the eyes and support healthy vision.
NATURE’S ANSWER EYEBRIGHT alcohol-free extract is absorbed faster than tablets or capsules and is holistically balanced so that the constituents of the extract are in the same synergistic ratios as in the source plant.