Macular Degeneration





Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the number one cause of progressive vision loss and blindness in developed countries.  Of Americans over age 65, at least 10% have some loss of vision due to AMD and as many as 30% of Americans over the age of 75 are affected.  

My grandmother, her two sisters, and now my uncle have all had their struggle with this terrible, yet preventable illness.  Thankfully, although I may be carrying this disease in my genetics, I do not necessarily have to suffer from it.  In this case, a healthy diet may mean a healthy gene expression. 

AMD comes in two forms: Non-exudative AMD (also known as dry or atrophic AMD) and exudative AMD (also known as wet AMD).  Greater than 90% of people with AMD have dry AMD, which slowly progresses over a number of decades. Wet AMD, in contrast, is associated with neovascularization, retinal edema, and hemorrhage, and results in rapid vision loss, frequently over a number of months.

Pathophysiology:

Retinal pigment epithelial cell degeneration is the description of age-related macular degeneration.  This degeneration results in a loss of the associated rods and cones.   Doctors still do not clearly understand the etiology of AMD, but it seems to include the accumulation of lipofuscin (a brownish pigment that remains after damaged blood cells have been broken down and absorbed) within retinal cells.  The accumulation of lipofuscin occurs as a result of oxygen-induced free radical damage or ultraviolet light damage to cell membranes. 

Risk:

The risk for developing AMD is partially determined by genetics, but because new scientific research has demonstrated a relationship between food and gene expression, I believe that having a genetic predisposition to AMD does not necessarily mean you will develop it. Currently, there is no known effective Western medical treatment for dry AMD. Wet AMD may be treated using medications that inhibit angiogenesis and laser photocoagulation. 

What a person with AMD might see

Observational studies have demonstrated that high consumption of cholesterol, total fat, saturated fat, and linoleic acid have each been associated with an increased risk of AMD.  The relationship between amount of linoleic acid (an essential fatty acid) and AMD may be the result of the use of linoleic acid (which is converted to toxic peroxides at high temperatures) for cooking.  Many vegetable oils contain this compound.  

In contrast, high intake of fish, and moderate wine consumption have been associated with a decreased risk of AMD, and foods rich in the carotenoids, lutein and zeaxanthin may aid in the prevention of AMD or slowing its progress.

Nutritional Supplementation:

As we age, our nutritional status tends to decline due to a combination of factors.  Firstly, gastrointestinal absorption naturally becomes less efficient with advancing age, which results in reduced cellular uptake of nutrients.  If we combine a poor diet with this naturally decline in a physiological process, we increase our chances of nutritional deficiency.  Furthermore, suboptimal nutritional status may be especially detrimental to the special sense organs involved in smell, taste, hearing and vision. 

Lutein and Zeaxanthin:

Lutein and zeaxanthin are dietary carotenoids.  They are found in higher concentrations in the macular region of the retina than in plasma and other tissues.  Macular pigment is primarily composed of these two carotenoids.  The most important role of lutein and zeaxanthin is to filter the phototoxic blue-light  portion of the sun's rays, thereby providing a protective effect on the macula. 

Due to the fact that AMD may be the result of oxidative damage, supplementation with antioxidants may slow its progression.  In addition, certain nutrients such as lutein, zinc, and taurine play a crucial role in metabolic functions of retinal tissues.  As a result, increasing consumption of these nutrients might enhance the function of retinal cells that are still living, thereby improving vision as well as aiding in the prevention of retinal degeneration.  The concentration of lutein and zeaxanthin in the macula is partially dependent on their dietary intake, which is why supplementation can be so important. 

Fish Oil:

Docosahexaenoic acid (DHA) is a fatty acid present in fish oil, and has been linked with improvement in AMD patients. 

Zinc:

Research has shown than zinc supplementation has been beneficial in the treatment of AMD.  Zinc plays a crucial role in visual function. Higher concentrations of zinc are found in the eye than in most other bodily tissues, and its effects on vision happen in a few important ways. Firstly, zinc is a cofactor for enzymes involved in visual function. Secondly, zinc helps to stabilize cell membranes and has anti-oxidant properties. 

Research has shown that avoiding zinc deficiency in some elderly individuals may require higher consumption of zinc than the Recommended Dietary Allowance.  Furthermore, such persons may have a greater susceptibility to the negative effects of deficient zinc intake than others in that population.  With regards to patients with AMD, their mean serum concentration of zinc was found to be significantly lower than that of an age-matched control group. 

Caution: Supplementation of zinc may interfere with copper absorption, thereby causing copper deficiency. Therefore, co-administration of copper is necessary. 

B Vitamins:

Atherosclerosis is thought to be an important contributing factor in the pathogenesis of AMD.  One crucial risk factor in the development of atherosclerosis is hyperhomocysteinemia.  Furthermore, observational studies have demonstrated a positive relationship between the levels of homocysteine in the blood and the risk of developing AMD.  Folic acid, vitamin B6 and vitamin B12, taken together as supplementation, has been shown to reduce homocysteine levels.            

Glutathione:

Glutathione is a very important antioxidant and is found in ocular tissues, including the retina.  Based on the report of one practitioner, a series of intravenous glutathione treatments has been shown to improve both dry and wet AMD.

Melatonin:

There may be a few explanations as to why melatonin could help with the treatment or prevention of AMD.  Firstly, levels of melatonin decline with age, which may play a role in the pathogenesis of AMD.  Secondly, melatonin has a large role in regulating the mount of light that reaches photoreceptors of the eye through its regulation of eye pigmentation.  Lastly melatonin’s role as an antioxidant may help to protect the epithelial cells of retinal pigment from oxidative damage.  

Ginkgo Biloba Extract:
Ginkgo plays a role in the prevention of free radical-induced damage and also enhances blood flow.  

Taurine:

The retina contains high concentrations of taurine, with most of it located in the photoreceptor cell layer.  The functions of taurine appear to be its action as a cellular buffer, thereby protecting cells from the detrimental effects of toxins, ultraviolet light and osmotic changes.  Although humans are capable of synthesizing taurine from cysteine, adequate amounts of taurine are partially dependent on dietary intake.

Anthocyanosides:

Anthocyanosides are a group of flavonoids and are the main component of bilberry, an herbal supplement. Anthocyanosides are also present in blueberries, as well as some other fruits and vegetables.  Anthocyanosides act as antioxidants and experts believe that also act as biochemical amplifiers in retinal photoconduction.  Research has shown that supplementation with anythocyanosides to healthy volunteers has resulted in improved markers of visual function, such as macular sensitivity and dark adaptation.  Furthermore, patients with diabetic retinopathy demonstrated reduction in the degree of hemorrhage in retinal vessels as well as improved capillary integrity.    

Selenium:

Selenium is an antioxidant that is found in large concentrations in the retina.  Therefore, it is thought that its antioxidant action may help to prevent oxidative damage that leads to AMD.

As Naturopathic Doctors, we strive to treat each patient as an individual.  Therefore, it will be necessary to consult with your licensed Naturopathic Physician for proper administration of these supplements, as well as for proper diet and nutrition counseling. 

Other Considerations:
Ozone Therapy- Major Auto Hemo Therapy (MAH)