Natural treatments for macular degeneration
Natural treatments for macular degeneration focus on supporting vision health through dietary and supplemental approaches. Macular degeneration, a condition characterized by the gradual deterioration of the macula in the retina, is a leading cause of vision impairment, particularly in older adults. Prominent natural treatments include carotenoids such as lutein and zeaxanthin, which are believed to protect the macula from light damage and may improve vision in some individuals. Zinc, often combined with antioxidants, is also recommended based on research indicating it may slow disease progression, although concerns about high doses exist.
Other potential treatments include beta-carotene, bilberry, ginkgo biloba, and omega-3 fatty acids; however, while observational studies suggest benefits, more rigorous clinical trials are needed to confirm their effectiveness. A balanced diet rich in fruits, vegetables, and low-glycemic-index foods is advised, alongside lifestyle modifications like avoiding smoking. While some studies indicate that certain dietary components may lower the risk of macular degeneration, the evidence remains inconclusive. Overall, these natural treatments are meant to complement standard medical care rather than replace it, emphasizing the importance of consulting healthcare professionals for vision concerns.
Natural treatments for macular degeneration
DEFINITION: Treatment of the gradual deterioration of the macula, an area of the retina.
- PRINCIPAL PROPOSED NATURAL TREATMENTS: Carotenoids (such as lutein and zeaxanthin), zinc with or without antioxidants
- OTHER PROPOSED NATURAL TREATMENTS: Beta-carotene, bilberry (Vaccinium myrtillus), ginkgo, low-glycemic-index diet, oligomeric proanthocyanidins, curcuma or turmeric, vitamin E, vitamin C
Introduction
The lens of the eye focuses an image on a portion of the retina called the macula, the area of finest visual perception. Gradual deterioration of the macula is called macular degeneration. After cataracts, damage to the macula is the second most common cause of visual impairment in individuals over sixty-five. Smoking, high blood pressure, and atherosclerosis are associated with progressive damage to the macula. Ultraviolet light may also play a role by creating harmful free radicals in the eye.
In the most common form of macular degeneration (dry macular degeneration), a substance known as lipofuscin accumulates in the lining of the retina. A much less common form of macular degeneration involves the abnormal growth of blood vessels (wet macular degeneration). This can be treated successfully if attended to soon enough, but it may lead to irreversible blindness if left untreated. For this reason, medical consultation in all cases of macular degeneration (or any other type of vision loss) is essential.
Principal Proposed Natural Treatments
The treatments described in this section are intended as support to standard ophthalmological care, not as a substitute for it. In addition, all studies refer primarily to the more common type of macular degeneration, dry macular degeneration.
Zinc and antioxidants. The longitudinal double-blind, placebo-controlled Age-Related Eye Disease Study (AREDS) from 1992 to 2001 evaluated the use of zinc with or without antioxidants in patients with early stages of macular degeneration. The study found that a combination of nutrients called the AREDS formula may help slow the progression of macular degeneration. The National Eye Institute supports using the AREDS formula, which contains 500 milligrams (mg) of vitamin C, 400 mg of vitamin E, 15 mg of beta-carotene, 80 mg of zinc, and 2 mg of copper. Some supplements, like Ocuvite PreserVision, contain all these nutrients in one pill. However, the study results are unclear as to whether the antioxidant portion of this mixture added any additional benefit. Zinc at doses of 80 mg and higher daily can be harmful because it impairs copper absorption, which is why extra copper was provided in the AREDS study.
There is no convincing evidence that antioxidants alone are effective for preventing or delaying the onset of macular degeneration. A four-year, double-blind, placebo-controlled trial of 1,193 people with macular degeneration failed to find vitamin E alone helpful for preventing or treating macular degeneration. An even larger and longer study, following more than twenty thousand people for more than ten years, failed to find that beta-carotene alone reduced the incidence of macular degeneration. A mixture of beta-carotene, vitamin E, and vitamin C has also failed to prove beneficial. A review of three randomized controlled trials involving 23,099 subjects found no evidence of benefit for vitamin E and beta-carotene.
Lutein and other carotenoids. Carotenoids are a group of substances found in many fruits and vegetables, especially those that are yellow-orange and dark green. (Beta-carotene is the best-known carotenoid.) Observational studies suggest that a higher intake of dietary carotenoids is associated with a lower incidence of macular degeneration. However, observational studies prove little about cause and effect. Double-blind, placebo-controlled studies are necessary to determine whether carotenoids can prevent or treat macular degeneration.
In the large study mentioned, beta-carotene failed to prove effective for preventing macular degeneration. However, the less well-known carotenoids lutein and zeaxanthin might be more promising. These carotenoids, principally found in corn and dark-green leafy vegetables, are found in high concentrations in the eye. It has been suggested that they may protect the macula from light-induced damage by dyeing it yellow, thereby acting as a kind of natural pair of sunglasses. They also act in the usual antioxidant fashion by neutralizing free radicals.
These hopes received support from a double-blind, placebo-controlled trial that enrolled ninety people with dry macular degeneration and followed them for twelve months. The participants received either lutein (10 mg), lutein plus antioxidants, and a multivitamin-multimineral supplement, or a placebo. At the end of the study period, participants who had taken lutein alone or lutein plus the other nutrients showed improvements in vision, while no change in vision was seen in the placebo group. A subsequent study failed to find a benefit with lutein, but it used a lower dose (6 mg daily) and involved fewer people. Ultimately, further study will be needed to establish whether lutein is helpful for macular degeneration.
Other Proposed Natural Treatments
Like carotenoids, flavonoids are found in many plants and may offer a variety of beneficial effects. Weak but interesting evidence suggests that bilberry and oligomeric proanthocyanidins, both rich in flavonoids, may prevent or treat macular degeneration.
The herb Ginkgo biloba contains many flavonoids and is thought to increase circulation. In a six-month, double-blind, placebo-controlled study of twenty people with macular degeneration, using ginkgo at 160 mg daily resulted in improved visual acuity. Furthermore, positive results were seen in a twenty-four-week double-blind study of ninety-nine people with macular degeneration that compared ginkgo extract at a dose of 240 mg per day with ginkgo at a dose of 60 mg per day. Vision improved in both groups but to a greater extent with the higher dose. This study would have been more meaningful if it had included a placebo group, but nonetheless, “dose-related” effects of this type hint that a treatment may work. It has been suggested that ginkgo aids vision by increasing blood flow to the optic nerve. However, one study designed to evaluate this possible mechanism of action failed to document such an effect.
In observational studies, people who consume a diet rich in omega-3 fatty acids (fish oil) seem to lower their risk of macular degeneration. However, without randomized-controlled trials, it is impossible to say whether omega-3 produces this benefit. One controlled study that failed to use a placebo group appeared to find benefits from a combination of acetyl-L-carnitine, fish oil, and coenzyme Q10. Another study found the fatty acid alpha-linolenic acid may increase the risk of macular degeneration. Additionally, increasing one's intake of fatty fish rather than taking a supplement can result in ingesting extra mercury, depending on the type and origin of the fish.
Other proposed treatments include curcumin or turmeric, polyphenols, saffron, milk thistle, and vitamin C, though they have yet to be scientifically proven. Maintaining a diet rich in nutritious food and avoiding smoking is advisable. Weak evidence hints that moderate wine consumption might help prevent macular degeneration. Similarly weak evidence suggests possible benefits of a low-glycemic-index diet.
Bibliography
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