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Nutrition plays an enormous role in the prevention and treatment of the leading causes of impaired vision in North America—cataracts and macular degeneration. More than 2 million Americans age 50 and older have advanced age-related macular degeneration (AMD), according to the National Eye Institute, a stage that can lead to severe vision impairment. Cataracts (a cloudy covering of the lens) affect nearly 22 million Americans age 40 and older—by age 80, half of all Americans develop cataracts. In both of these conditions, the normal protective mechanisms are unable to prevent damage to the lens and macula.
A diet high in richly colored fruits and vegetables is associated with a lowered risk for cataracts and macular degeneration. Initially, it was thought that this protection was the result of increased intake of antioxidant vitamins and minerals. However, various “non-essential” food components, particularly non- provitamin A carotenes like lutein, zeaxanthin, lycopene, and flavonoids, have proven to be even more significant in protecting against cataracts and macular degeneration than traditional nutritional antioxidants like vitamins C and E and selenium.
Dietary supplements can be vital in maintaining eye health, preventing these diseases, and improving visual function if these conditions develop. Here are the top five for eye health.
Key Nutrient #1: Lutein
Critically important to the health of the macula, especially the central portion of the macula (technically known as the fovea), are the carotenes lutein and zeaxanthin. In fact, the fovea owes its yellow color to its high concentration of lutein and zeaxanthin. These yellow carotenes function in preventing oxidative damage to the retina, and play a central role in protecting against the development of macular degeneration.
A low level of lutein and zeaxanthin within the macula represents a major risk factor for macular degeneration, as patients with this condition have 35–40% less lutein in their maculas than people without macular degeneration.
In addition, new research shows that supplementing the diet with lutein and zeaxanthin not only helps to protect against macular degeneration, it can also actually improve visual function in people who have the disease. Specifically, in subjects with macular degeneration, 10 to 15 mg of lutein daily has led to significant improvements in several objective measurements of visual function, including glare recovery, contrast sensitivity, and visual acuity. Patients taking a minimum of 10 mg of lutein daily also experienced a 50% increase in macular pigment density.
Lutein is also important in preventing cataracts—and in improving visual function in people with existing cataracts. Like the macula, the lens concentrates lutein and zeaxanthin. In fact, these are the only carotenes found in the lens. Three large studies have shown that the intake of lutein was inversely associated with cataract surgery. In other words, the higher the intake of lutein, the less the likelihood cataract surgery would take place.
Key Nutrient #2: Flavonoid-Rich Extracts
Flavonoid-rich extracts of blueberry, bilberry, pine bark (Pycnogenol), or grape seed also offer valuable benefits in protecting and improving eye health.
In addition to possessing excellent antioxidant activity, these extracts have been shown to improve blood flow to the retina as well as improve visual processes, especially poor night vision.
Key Nutrient #3: Nutritional Antioxidants
Nutritional antioxidants like beta-carotene, vitamins C and E, zinc, copper, and selenium are extremely important for eye health. While research has often focused on just one of these nutrients, studies conducted by the Age-Related Eye Disease Study (AREDS) research group confirm that a combination of these nutrients produce better results than any single nutrient alone.
But even something as simple as taking vitamin C or zinc can be strongly protective. Several studies have demonstrated that vitamin C supplementation can prevent cataract formation, halt cataract progression, and, in some cases, significantly improve vision. One study showed that women who took vitamin C supplements for more than 10 years had a 77% lower rate of cataract formation compared to women who did not take a vitamin C supplement.
Zinc is perhaps the most important mineral for eye health, as it plays an essential role in the health of the retina. It is also required as a component of the antioxidant enzyme super oxide dismutase (SOD), which helps to protect the eyes against AMD. Levels of zinc have been shown to be low in over 90% of cataract patients. Zinc is also involved in protecting against macular degeneration. A two-year double-blind, placebo-controlled trial involving 151 people demonstrated that the group taking a zinc supplement had significantly less visual loss than the placebo group.
Key Nutrient #4: Coenzyme Q10 (CoQ10) and Acetyl-L-Carnitine
Together, these two nutrients play a critical role in energy production. The role of CoQ10 in our cells is similar to the role of a spark plug in a car engine, while acetyl-L-carnitine functions as the fuel injection system. Just as the car cannot function without that initial spark, cells in our body cannot function properly without CoQ10 and carnitine. CoQ10 and carnitine perform their functions primarily in the mitochondria—the energy producing compartments within cells.
Although the body makes some of its own CoQ10 and carnitine, considerable research shows significant benefits with supplementation. This is especially true for people with heart disease, including high cholesterol levels, high blood pressure, and those taking cholesterol-lowering drugs. In terms of eye health, the mitochondria within the retina are especially vulnerable to toxic byproducts of cell metabolism, making supplementation with acetyl-L-carnitine (a highly absorbable form of carnitine) and CoQ10 especially important. In one study, a combination of acetyl-L-carnitine (200 mg), omega-3 fatty acids (a combination of 460 mg of EPA and 320 mg of DHA), and CoQ10 (20 mg) was shown to improve visual function and halt damage to the eye in the early stages of macular degeneration. In addition, this combination stopped the disease from progressing in 47 out of 48 cases.
Key Nutrient #5: Fish Oils
There is a strong relationship between hardening of the arteries (atherosclerosis) and eye health. So, just as in atherosclerosis, omega-3 fatty acids from fish oils play an important role in the prevention of eye conditions like macular degeneration. The recommended dosage of a fish oil supplement to support eye health is enough to provide approximately 1,000 mg of EPA and DHA.
Foods rich in the carotenes lycopene, zeaxanthin, and lutein include bell peppers, carrots, collard greens, kale, papaya, spinach, sweet potatoes, and tomatoes.
SAY GOODBYE TO DRY EYE
Try these natural solutions—you may be able to toss your prescription drops
Tears, released from the lacrimal glands in the eyelid, are important for lubricating the eye and preventing inflammation and infection. Dry-eye syndrome results when the quantity of tears is insufficient to keep the eye lubricated. This syndrome causes irritation of the cornea and other tissues. It is sometimes associated with sicca syndrome, an autoimmune disease, but it often occurs in people who are otherwise healthy.
Dry eye can be caused by a lack of vitamin A, which is necessary for health of the epithelial cells. These cells generate the mucus that mixes with tears to lubricate the eye. In one study, topical application of vitamin A drops improved dry eye significantly, even when compared to a widely used drug. Vitamin A has helped people with dry eye from a variety of causes, such as keratoconjunctivis (inflammation of the cornea and conjunctiva), xerophthalmia (a deficiency of tears), or contact-lens-induced dry eye.
Studies show omega-3 and omega-6 fatty acids, taken along with vitamins C and B6, can also be effective. A multivitamin-mineral containing vitamins C, E, and B6; zinc; and selenium can help to improve dry eye and boost the immune system, and eye drops containing antioxidants can be effective. Try Life Extension Brite Eyes III Eye Drops.
Excerpted from The Vitamin Cure for Eye Disease: How to Prevent and Treat Eye Disease Using Nutrition and Vitamin Supplementation by Robert G. Smith, PhD (Basic Health Publications, 2012).
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Michael T. Murray, ND, is the author of more than 30 books on natural health, including The Encyclopedia of Natural Medicine, Third Edition. He is regarded as one of the world’s top authorities on natural medicine, and is a sought-after lecturer and educator. Visit him online at doctormurray.com.