Eye Health: Protecting Your Vision
Degenerative eye diseases of various kinds may begin to affect individuals as young as the age of 50 (age-related macular degeneration) as well as those with diabetes mellitus (diabetic retinopathy). Even though symptoms may not appear until later in life, damage begins at an earlier age as a result of factors including sun exposure (ultraviolet light radiation), a nutrient-depleted diet, and poor lifestyle such as uncontrolled blood glucose levels and/or exposure to cigarette smoke.
Both age-related macular degeneration and diabetic retinopathy are characterized by dysfunction of the small blood vessels in the retina and oxidative damage; over time, this leads to gradually distorted vision and potentially blindness. The small blood vessels may “overgrow” into the retina, or they may become “leaky”. Several key nutritional agents have been shown to help protect the retina from this type of damage. These include lutein, zeaxanthin, zinc, omega-3 fatty acids, as well as the antioxidants found in blueberries. Ginkgo is an herb that has also been found to help improve eye health.
The LUTEGA study recently found that a nutritional supplement providing a combination of lutein, zeaxanthin, omega-3 fatty acids, and other antioxidants resulted in significant improvements in the density of pigment in the area of the retina called the “macula”; this is also known as macular pigment optical density (MPOD). This is important because the role of macular pigment is to protect the sensitive retinal cells from oxidative damage, including exposure to UV light. In the study, patients with age-related macular degeneration were treated with 10 mg of lutein, 1 mg of zeaxanthin, and a small dose of omega-3 fatty acids (130 mg), one to two times per day for one year. At the end of one year, MPOD increased in the treatment group, but decreased significantly in the placebo group.
Another study, the CLEAR study, further found that, in addition to increasing macular pigment and protecting against oxidative damage, supplementation with lutein can actually prevent vision loss. Over a one-year period, during which patients with age-related macular degeneration were supplemented with lutein, those given the supplement experienced no change in their visual acuity. On the other hand, those given placebo had a significant decrease in their vision.
Other research has demonstrated associations between higher levels of eicosapentaenoic acid (EPA) in the blood and decreased risk of a more serious type of macular degeneration. This type of degeneration is called neovascular macular degeneration, where there is an overgrowth of small blood vessels in the retina. In this study, those subjects with the highest EPA blood levels had a 75% lower odds of having age-related macular degeneration.
Ginkgo also has beneficial effects on the blood vessels of the eye as well as antioxidant effects. In patients with normal-tension glaucoma, supplementation with ginkgo has been shown to significantly improve blood flow to the eye, compared with placebo. Another study found improvements in visual function associated with ginkgo in children and adolescents with long-standing type I diabetes after only three months. Finally, a study in patients with age-related macular degeneration found that among those taking 240 mg of standardized ginkgo extract, there was a marked improvement in visual acuity compared to patients taking a low dose of 60 mg per day; this was after a period of six months.
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