Conscious Choice: A New Look at Eye Health

January 2003 | Health Conscious

A New Look at Eye Health

by Bill Sardi

Many people with deteriorating vision are seeing nutritional therapy as a successful alternative to conventional medicine or surgery. An example is Mildred Frank of Ormond Beach, Florida, who experienced a dramatic improvement in her vision that was not the result of lasers or lens implants. Her vision improvement began with a can of kale.

Frank had two retinal disorders: macular degeneration, which is the loss of central vision, and retinitis pigmentosa, which initially manifests as night blindness and progresses to a permanently constricted field of vision. Frank’s friend said kale might help resolve her eye troubles, so she began eating a can of cooked kale a day. Within weeks she noticed some improvement in her vision.

Although anecdotal, Frank’s success with nutritional therapy isn’t unprecedented. Vision researchers recognize that lutein and zeaxanthin — plant pigments plentiful in collards, kale, mustard greens and spinach — play important roles in maintaining a healthy visual system. Lutein supplements have been available since 1995; commercially, it is extracted from marigold flower petals.

Lutein and zeaxanthin work because they act like sunglass filters to protect the retina. The retina, about the size of a postage stamp, contains millions of light receptor cells. Normal, healthy retinas exhibit a yellow spot in their visual center, the macula. Lutein and zeaxanthin are concentrated in the central retina, overlying the macula, a pinpoint-wide zone where color vision and central vision is produced. Yellow pigmentation of the central retina of animals disappears when lutein and zeaxanthin pigments are removed from the diet.

Note that foods such as cantaloupe, carrots, sweet potato, yams and yellow squash are rich in beta-carotene but provide no lutein. Dark-green leafy vegetables such as collards, kale, mustard greens and spinach are rich sources of beta-carotene as well as lutein and zeaxanthin.

Although kale therapy is far from mainstream, researchers are observing connections between nutrition and macular degeneration, cataracts, and glaucoma.

Protect Against Cataracts

The focusing lens of the human eye, about the size of an aspirin tablet, is the only organ that never sheds a cell. It receives nutrients indirectly via the aqueous fluid rather than the bloodstream. The lens of the eye is under unusual stress because it is exposed to constant bombardment by solar, ultraviolet radiation through the transparent cornea. But sufficient data exist that nutritional therapy may help prevent cataracts.

In 1990, a study at the University of Western Ontario in Canada, compared adults with cataracts to those without. It found that taking 300-to 600-mg supplemental vitamin C reduced cataract risk by 70 percent and 400-IU supplemental vitamin E for more than a year reduced cataract risk by 50 percent.

The focusing lens is also sensitive to high blood-sugar levels, which can cause inflammation, vision changes and eventually diabetic cataracts. Sugar can oxidize and harden in the lens, a destructive process among diabetics that can be countered by nutrients such as inositol. Bioflavonoids, such as quercetin, are known to inhibit the enzyme that promotes diabetic cataracts.

Diet plays a significant role in cataract risk. Individuals who do not eat five servings of fruits and vegetables per day are 5 to 13 times more likely to develop cataracts.

Reverse Macular Degeneration?

Most patients with macular degeneration are given a poor prognosis for their failing central vision. This has been changing slowly since a 1994 report showed that the equivalent of 6 mg of lutein per day obtained from a diet rich in dark-green leafy vegetables significantly reduces the risk of advanced macular degeneration.

Researchers at the Schapens Eye Research Institute in Boston report that 60-year-olds with normal levels of lutein and zeaxanthin in their retinas exhibit the visual sensitivity of 20-year-olds.

Lutein and zeaxanthin are not limited to protective roles in the retina only. They may also prevent cataracts, a cloudy focusing lens, and glaucoma — an optic nerve disease.

Nutrition and Glaucoma

For decades, eye doctors have approached glaucoma as a loss of peripheral vision caused by elevated fluid pressure in the eye that damages the optic nerve. However, eyes with normal fluid pressure can also lose peripheral vision. Now researchers suspect a nerve toxin may be involved in a common form of glaucoma.

While nerve-protective drugs may take years to develop, an array of natural nerve protectors may be able to minimize glutamate toxicity. These include vitamin B12, SAMe (S-adenosylmethionine), ginkgo (Ginkgo biloba), vitamin E, coenzyme Q10, folic acid, and magnesium.

Additionally, various studies reveal that Greenland Eskimos have lower rates of glaucoma than other Caucasian populations, an observation attributed to the consumption of omega-3 fish oil. Research indicates that omega-3 fats appear to help prevent optic nerve disorders.

With advancing age, the likelihood of macular degeneration, cataracts, and glaucoma increases. The baby boomers will soon swell the population of retirees in the United States, with inevitable increases in eye disease and sight loss. The best answer to stem the tide of age-related vision problems is prevention. Nutrition tops the list of preventive measures for age-related eye disorders.

Bill Sardi is a health journalist in Diamond Bar, California, and the author of The Iron Time Bomb (Bill Sardi, 1999).

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