Eat for Your Eyesight
Victoria Shanta Retely

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In our aging nation, it's not surprising that age-related deteriorating eye conditions are increasing. From birth, our eyes filter light--from sunlight to the more damaging blue light (light waves that make the sky look blue) with detrimental effects over time.

Age-related macular degeneration (AMD), a disease associated with aging that gradually destroys one's central vision, is the largest cause of vision loss in the U.S., affecting five percent of people aged 65 and older. AMD is debilitating; it can obstruct your ability to see the details of someone's face, or read a book or road sign. And once AMD progresses, there's no turning back.

Eye health is contingent upon multiple factors. According to the National Eye Institute (NEI), the greatest risk factor for AMD is age (over age 60), followed by smoking, obesity, race (Caucasians are more prone than African-Americans), family history (an immediate relative with AMD), and gender (women are more susceptible than men). But AMD is preventable.

Just like your skin, your eyes need "sunscreen," too. Eating wisely can be a protective salve for your eyes. New research suggests that key foods and nutrients might be a simple, inexpensive treatment option to help protect vision.

Enter the Age-Related Eye Disease Study. The last two decades of research have generated vital data on eye health and nutrition. Specifically, the Age-Related Eye Disease Study (AREDS), a 2001 clinical trial led by researchers at the Tufts University Jean Mayer USDA Human Nutrition Research Center for Aging, shed light on nutrients that fend off vision loss from advanced AMD. AREDS found that in 3,640 people with intermediate signs of AMD, high doses of zinc oxide, copper (to balance out zinc supplementation), and the antioxidants vitamin C, vitamin E and beta-carotene (vitamin A) significantly reduced the risk for developing advanced AMD.

In fact, high potency antioxidant and/or zinc supplementation taken daily reduced the risk of advanced AMD by 25 percent, according to the study findings, published in the Archives of Ophthalmology in December 2003. Scientists believe that one explanation for the benefits behind the antioxidant formulation might be the reduction of oxidative stress.

The next generation study, AREDS2 (scheduled for completion in 2012), takes the formula a step further by adding the carotenoids (naturally-occurring plant pigments) lutein and zeaxanthin, and/or the omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to the AREDS formula to see if it slows the progression of AMD among 4,000 participants aged 50 to 85 years.

In addition, the study will look at the effects of eliminating beta-carotene and reducing zinc in the original AREDS supplement.

"AMD is a complicated scenario. The interaction of a number of genes and lifestyle factors may come into play," explains Emily Chew, M.D., Deputy Director, Division of Epidemiology and Clinical Applications at NEI. "AREDS2 is looking at people who are already at high-risk for advanced AMD and evaluating whether high dose supplementation of lutein and zeaxanthin or omega-3 fatty acids is beneficial. If not, why use it?"

COLORFUL CAROTENOIDS FOR EYE HEALTH

Looking for another reason to eat leafy greens like kale and spinach?

These vegetables are high in two eye-protective carotenoids, lutein and zeaxanthin, which earned the attention of AREDS2 researchers.

Yellow foods like corn and egg yolks also contain high levels.

Hens eat carotenoid-rich corn and marigold petals and pass those nutrients into their eggs' yolks.

Deposits of these carotenoids form the macular pigment in your eye's retina. According to research in the July 2006 Journal of Nutrition, macular pigment may reduce oxidation and free-radical damage in the central retina by absorbing harmful wavelengths of light. That's why eye health experts advise people to consume at least six milligrams (mg) per day of lutein and zeaxanthin from foods to reduce the risk of AMD and cataract formation. The AREDS2 supplement contains 10 mg of lutein and two mg of zeaxanthin.

Eying omega-3 fatty acids.

Researchers have also homed in on omega-3 fatty acids for potential eye health benefits. DHA is largely present in the eye's retina. And, omega-3 fatty acids' powerful anti-inflammatory properties hold promise for fending off eye diseases like AMD, which is believed to be rooted in inflammation.

In the December 2009 issue of the American Journal of Clinical Nutrition, researchers followed 1,837 AREDS participants with moderate to high risk for AMD, concluding that those who consumed the most omega-3 fatty acids (primarily from fish and seafood) were 30 percent less likely to progress to advanced AMD. This explains why AREDS2 is examining the potential for 1,000 mg per day of the omega-3 fatty acids, DHA and EPA to halt the progression of AMD.

Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC

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