The Link Between Diet and Eye Disease

Eye disease is one of the most common causes of permanent disability in the United States. More than 20 million Americans age 40 and older have cataracts, and 10 million Americans age 60 and over have age-related macular degeneration (AMD). These eye diseases occur as we grow older, and proper nutrition may have some affect on both of them.

Cataracts develop on the lens of the eye when the proteins in the lens are damaged. These proteins are responsible for keeping the lens clear. When they become damaged, the lens becomes cloudy or opaque, and your vision may become blurry. You may also have poor night vision or double vision with cataracts. Cataract surgery is often necessary to remove and replace the damaged lens with an artificial lens.

AMD occurs when cells in the macula of the eye die. The macula is located in the center of the retina in the back of the eye, and is responsible for your sharp, central vision, which you need for reading and other tasks that require good eyesight. Once the macula is damaged, your vision is no longer clear, and you cannot make out fine details of objects. There is no cure for AMD, but proper nutrition may help prevent it from worsening.

Diet and Eye Disease: What Is a “Healthy Eyes” Diet?

According to Nelson, the nutrients associated with eye health are vitamins C and E; carotenoids, beta carotene, lutein, and zeaxanthin; omega-3 fatty acids; zinc; and vitamins B6, B9 (folic acid or folate), and B12.

“Antioxidants, especially lutein, help deter build-up of waste products in the retina, which in turn helps reduce your risk for AMD,” says Jennifer K. Nelson, MS, RD, director of clinical dietetics and associate professor of nutrition at the Mayo School of Health Sciences in Rochester, Minn. “Folate and vitamin B6 decrease the presence of the blood chemical homocysteine, which lowers your risk for AMD. Antioxidants also help prevent the cross linking of proteins in the lens which can cause cataracts.”

Here's a list of foods containing eye-healthy nutrients:

• Fruits and vegetables (good sources of vitamins C and E)
• Dark green vegetables such as kale and spinach (lutein, vitamin E)
• Yellow and orange fruits and vegetables (beta carotene and zeaxanthin)
• Anchovies, herring, mackerel, salmon, sardines, trout, tuna, and white fish (omega-3 fatty acids)
• Beef, eggs, lamb, milk, peanuts, pork, and whole grains (zinc)
• Bananas, chicken, dried beans, fish, liver, pork, and potatoes (vitamin B6)
• Citrus fruits, fortified cereals, dried beans, green leafy vegetables, liver, mushrooms, nuts, and peas (folic acid)
• Dairy products, eggs, meat, poultry, and shellfish (vitamin B12)

A diet high in refined carbohydrates, such as white rice, white bread, and pasta, may actually increase your risk of developing AMD. These foods have a high glycemic index, which means they are broken down rapidly into blood glucose or sugar. Choose breads and pasta made from whole grains and brown rice for your complex carbohydrates.

Diet and Eye Disease: Nutrition Supplements for Eye Health

In 2001, the National Eye Institute’s Age-Related Eye Disease Study (AREDS) found that taking a specific supplement of high doses of vitamin E, beta carotene, zinc, and copper may prevent intermediate AMD from progressing to the advanced stage. AREDS found no evidence that the supplement benefited anyone who showed no signs of AMD or those with early stage AMD. The AREDS-2 clinical trials are currently being conducted to look at the addition of lutein, zeaxanthin, and omega-3 fatty acids to the original AREDS formula.

For those with intermediate AMD who want to try the supplement formula, a discussion with your doctor is a must. “Because the AREDS-recommended supplement contains relatively high doses of antioxidants and zinc, you and your health care provider need to determine if the AREDS supplement is right for you,” cautions Nelson. “It is important that you do not self-medicate any supplements higher than the daily recommended intakes."

“We also need to look at the long-term effects of taking the AREDS supplement,” says Nelson. “For example, the AREDS formula has a very high level of beta carotene, which may increase the risk for lung cancer in smokers.” Nelson adds that eating a diet with plenty of green leafy vegetables, fish, and fortified cereals should make taking supplements for eye health unnecessary for most people.

“We’re only just beginning to look at nutrition and eye health, and it’s an exciting time because we have found such a link,” says Nelson. “A healthy diet is the foundation for healthy eyes.”