Scientific Summary
This protocol has provided background on age-related macular degeneration in terms of its nature, etiology, underlying physiology, pathophysiology, pharmacology, and nutrition. Basic information has been provided on AMD, including newer standard and non-standard approaches to treating this disease. The protocol has focused on the importance of nutritional solutions that prevent or treat AMD. Enough background information has been presented on AMD and its nutritional supplements to enable the reader to make informed decisions on the usefulness of nutrition and its effects on AMD.
There has been limited success within conventional medical treatment protocols to restore lost eyesight from either form of AMD. Leading researchers are documenting the benefits of more holistic approaches to AMD. Patients are encouraged to increase physical fitness, improve nutrition (including a reduction in saturated fats), abstain from smoking, and to protect their eyes from excessive light. Dietary supplementation with trace elements, antioxidants, and vitamins is recommended for improving overall metabolic and vascular functioning. Early screening and patient education offer the most hope for reducing the debilitating effects of the disease.
Functional Summary
The best approach to ensuring protection against the onset of age-related macular degeneration and the possible treatment of the condition involves an understanding of some of the main circumstances under which the condition arises. These are presented below followed by the recommended nutritional therapies for each problem.
- A reduction in the essential macular pigments, lutein and zeaxanthin, critical for the protection and proper functioning of the mechanisms required for the detection and imprinting of the light signals that come into the macula from the outside world.
As lutein and zeaxanthin are the essential pigments within the macula, it is critical to replenish them as they become depleted through the aging process. Consumption of foods rich in these substances is especially important since they have a direct affect on macular pigment density. When the pigment in the macula is denser, retinal tearing or degeneration is less likely. Lutein and zeaxanthin are found in yellow or orange vegetables, in dark leafy greens, and in fruits with yellow or orange hues. Egg yolk is a good source of lutein. Dietary supplements of lutein and zeaxanthin are recommended.
- A reduction in antioxidant levels within the retina and surrounding structures that make possible the presence and proliferation of free radicals that damage these structures and keep them from optimal functioning.
An increase in damaging free radical activity occurs through smoking, exposure to second-hand smoke, in diets high in saturated fats, cholesterol, and low in the “good fats” found in fish, whole grains and legumes. Smoking and high-fat diets are associated with AMD.
Decreased levels of natural antioxidants in the healthy eye are assocaited with AMD. Some of these essential natural antioxidants are glutathione, vitamin C, and the carotenoids, lutein and zeaxanthin. Dietary supplementation with these antioxidants protect against the progression of AMD. Other recommended antioxidants to protect the macula and retina include vitamin A, vitamin E, L-carnosine, taurine, lipoic acid, selenium, zinc (with copper), grape-seed extract, and coenzyme Q10.
- The onset of ocular atherosclerosis involves blockages in the choroidal blood vessels that adversely effects the functioning of the retina and, particularly, the macula.
Damaged blood vessels in the eye are associated with the onset of AMD. Blockages of these blood vessels, known as ocular atherosclerosis, raises blood pressure, creates deposits under the macula, and abnormal growth of blood vessels into the retina (choroidal neovascularization). The result is severe and debilitating neovascular AMD.
Dietary supplements are beneficial in treating ocular atherosclerosis. These include bilberry extract, ginkgo biloba, grape-seed extract, and genistein. Bilberry protects blood vessel walls and reduces leakage of capillaries, common in neovascular AMD. Ginkgo biloba improves blood flow and inhibits plaque accumulation in the blood vessels of the eye and maintains the elasticity of blood vessels. Grape-seed extract strengthens blood vessel walls, even shortly after ingestion. The phytochemical genistein, found in soy, inhibits blood vessel growth, slowing the progression of neovascular AMD.
Hydergine and thalidomide help with ocular atherosclerosis. Hydergine dilates blood vessels, stimulates mental functioning, and is effective in treating atrophic AMD. Thalidomide inhibits blood vessel growth and counteracts the progression of neovascularization in AMD patients.
General Precautions
Dietary supplements do not always positively effect health due to the systemic imbalances. Increasing evidence indicates that supplementation with one carotenoid may reduce serum levels of other carotenoids.61 Because there are more than 50 naturally occurring carotenoids, it is important that the correct supplement or combination of supplements be chosen. Mega-doses, beyond the prescribed dosage, are generally discouraged. Consult with healthcare professionals knowledgeable in the uses, dosages, and interactive effects of supplements to ensure the best nutritional therapy is utilized. |