August 19, 2014 in Features

Nutrition plays key role in eye disease prevention

By The Spokesman-Review
 


(Full-size photo)

Vision-friendly eating

The Mayo Clinic says these foods can contribute to better eye health.

Vegetables: Kale, collard greens, peppers, broccoli, sweet potato, spinach, peas, pumpkin, carrots and Swiss chard

Fruits: Peaches, blueberries, oranges, tangerines, mango, tomato, apricot, papaya, cantaloupe, honeydew, avocado and grapefruit

Sources of zinc: King crab, lamb, bulgur, lean beef, fortified breakfast cereals, beans, lean pork, dark meat from poultry, whole-wheat or buckwheat flours, pumpkin seeds

Omega-3-rich foods: Salmon, herring, tuna, mackerel, rainbow trout, sardines, flaxseed, English walnuts, canola oil, roasted soybeans

Yes, carrots are good for your eyes. But so are king crab, cantaloupe and canola oil.

While eating nutrient-rich food and maintaining a healthy weight won’t fix near- or farsightedness, they can help eyes work more efficiently – improving night vision and reducing light sensitivity, for example – and slow vision loss caused by eye diseases such as macular degeneration and diabetic retinopathy.

 “And it’s never too late to start,” said registered dietitian Jennifer Nelson, director of clinical dietetics and nutrition at the Mayo College of Medicine in Rochester, Minnesota, and a contributor to “The New Mayo Clinic Cookbook.”

Spokane optometrist Todd Wylie said he talks about nutrition with most of his patients, showing them pictures of the backs of their eyes and explaining the retina’s particularly high metabolic needs.

The eye needs more nutrients, more oxygen and more efficient waste removal than any other tissue in the body, said Wylie, of Advanced Eyecare & Optical.

“The eye is a window to the body,” he said. “There is so much activity going on there.”

With his patients, Wylie talks up the vision-related benefits of food grown close to home, noting local foods are more likely to be harvested ripe, when nutrients are peaking. He warns against nutrient-poor processed foods.

Chronic dehydration doesn’t help either, he said.

“As the blood gets sticky, and it can because of dehydration, it’s going to interfere with the ability of the blood to get into the microcapillaries,” Wylie said. “The retina, the back of the eye, is literally a sea of blood vessels.”

He’s backed up by a sea of research on the role of nutrition in vision, including two major eye disease studies by the federal government.

The Age-Related Eye Disease Study found that supplements containing high doses of vitamins C and E, beta-carotene, zinc and copper helped slow vision loss among certain patients – people with intermediate-stage macular degeneration that’s a result of aging. Ophthalmologists now recommend “AREDS-formula” supplements for people with the disease.

But unless you already have macular degeneration, an AREDS-formula supplement won’t help you, said Dr. Emily Chew, a deputy director at the National Eye Institute – part of the National Institutes of Health – who led the second study, called AREDS2.

“People always ask me: ‘Well, my mother has it. My father has it. Should I be on it?’ ” Chew said. “We don’t have any reason to put people like that on it, because it doesn’t affect the early stages.”

Instead, she encourages people worried about eye disease to get examined. Eye doctors can detect flecks in the eye called drusen that can indicate intermediate-stage macular degeneration before the patient suffers any loss of vision – and recommend nutritional supplements at that point.

AREDS2 sought to improve on the AREDS formula by testing supplements containing fish- and plant-derived nutrients – omega-3 fatty acids along with lutein and zeaxanthin. The additions didn’t help, according to findings released last year.

But other research has found that people who eat green, leafy vegetables and fish are less likely to get macular degeneration, Chew said.

“Healthy living’s important – no smoking, living healthfully and not being obese is all part of the picture of preventing … eye disease,” she said.

Excess weight can cause eye problems “from a plumbing standpoint,” Nelson said.

It raises the risk of high blood pressure, which can damage the small, delicate blood vessels in the eyes, Nelson said. It also can lead to Type 2 diabetes, which can lead to retina problems.


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