In focus: picture-perfect eye health - wellness

Better Nutrition, Sept, 2003 by Amber Ackerson

Reading glasses, retinal damage, cataracts, macular degeneration--as we age, they may all become an unexpected reality.

But the good news is that a diet rich in fresh fruits and vegetables--as well as certain dietary supplements--can play a major role in mitigating the seemingly inevitable process of eyesight deterioration.

Radical Action

Free radicals are among the usual suspects when it comes to dastardly deeds--and their oxidative effects can harm your eyes. That's why it's important for your diet to contain bioflavonoids, which neutralize free radicals. (See "Radical Solutions," p. 56, for more about free radicals and antioxidants.)

Berries--including blueberries, bilberries, strawberries, currants and cherries--contain a group of bioflavonoids known as anthocyanidins, which show specific benefits for the eye. Anthocyanidins are potent antioxidants that promote the strength and elasticity of tiny blood vessels, called microcapillaries, which supply blood to the eyes and optic nerve.

A related group of flavonoids, which are known as oligomeric proanthocyanidins (OPGs), have been shown to help reduce retina damage (retinopathy). This problem appears to be free radical-mediated and is seen more commonly in people who have high blood pressure, diabetes and a history of smoking.

An early French study reported that 150 milligrams (mg) daily of OPCs from grape-seed extract significantly reduced the progression of diabetic retinopathy. The bioflavonoid quercetin inhibits the action of the enzyme aldose reductase, which contributes to the development of diabetic retinopathy. As for quercetin supplements, the fat-soluble form is easiest to absorb, and naturopaths typically recommend 400 mg three times daily.

Vitamins for Vision

Then, of course, there are several vitamins and minerals with vision benefits. Vitamin C (200-1,000 mg/day) protects the eye from some of the damaging effects of light, including light-induced diminutions of photoreceptor cells, rod deterioration and loss of rhodopsin, a protein needed for retinal functioning.

Taking 15 mg/day of zinc may also be helpful. In double-blind human studies, zinc has been shown to both protect against--or otherwise slow down--the visual decline associated with age-related macular degeneration (AMD). This is important because AMD is the leading cause of blindness in industrialized countries.

What's more, selenium (100-200 micrograms/day) in combination with zinc appears to enhance these protective effects.

Taking vitamin E and a multiple vitamin may help reduce your risk of cataracts, according to a study in the May 1998 edition of Ophthamology. Scientists found that the risk of cataract development was reduced by 57 percent in people who regularly took vitamin E, and by 30 percent for those who took multiple vitamins regularly.

The amount of vitamin E taken by participants wasn't reported, but 400-800 International Units (IU) daily is most commonly recommended, although some leading researchers contend that no additional benefits are gained by taking more than 100-200 IU daily. Natural vitamin E (d-alpha tocopherol, or mixed natural tocopherols) is more active and better absorbed than synthetic vitamin E (dl-alpha tocopherol).

Some human studies suggest that ginkgo biloba leaf extract (GBE) may help to prevent retinal damage and improve vision in people with diabetic retinopathy and AMD. By augmenting blood flow to the opthalmic artery, GBE may also benefit people with glaucoma. Most studies use 120-160 mg (40 mg 3-4 times daily) of GBE standardized to contain 6 percent terpene lactones and 24 percent flavone glycosides.

Because ginkgo thins the blood, it should not be used by people scheduled for surgery, those who have clotting disorders or those on medications such as Coumadin or high-dose aspirin.

Virtuous Veggies

Finally, make sure you get plenty of vitamin A. Yellow and yellow-orange foods such as carrots, yams and cantaloupes are an excellent source of vitamin A as well as carotenoids--a group of antioxidant nutrients and vitamin A precursors.

Green leafy vegetables--broccoli, kale and spinach, and collard, turnip and mustard greens--are high in the carotenoids known as lutein and zeaxanthin. According to a number of recent studies, people with a diet rich in these foods are much less likely to develop age-related AMD and cataracts.

So even if your eyes are still the picture of health, it's never too early to begin taking care of them--from the inside out.