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Green Tea
and Macular Degeneration
Green tea has a great many health benefits. But can
it also protect your eyes and possibly ward off blindness? A study
published in the December 2006 issue of Brain Research suggests
that it might help.1 Specifically, the study found that green
tea’s EGCg can help decrease the oxidative stress that plays an
important part in the degeneration of the retina.
The biggest natural threats to your eyesight are
diseases causing degeneration of the retina, such as age-related macular
degeneration and glaucoma. Age-related macular degeneration affects the
part of the eye that allows you to see fine detail. It blurs the sharp,
central vision you need for "straight-ahead" activities like reading,
writing and driving and is the leading cause of blindness loss in people
over the age of 55. Glaucoma, the second leading cause of blindness, is
a group of diseases that results in damage to the optic nerve.
Oxidative stress (free radical damage) plays a part
in both of these diseases. The retinal neurons, which send messages to
the photoreceptor cells (rods and cones), are damaged by free radical
generators like UV light and smoking. The free radicals attack the
structure of the eye, wearing down its natural defense systems and
leading to the death of cells in the retina. As a result, vision fades,
sometimes to the point of being completely lost.
The scientists designing this study knew that green
tea’s EGCg had potent antioxidant abilities. So they set out to see if
EGCg could lessen oxidative stress to the retina and protect it from
damage. They induced oxidative stress via an intraocular (within the
eyeball) injection of sodium nitroprusside (SNP). SNP is known to cause
free radical damage to retinal tissue, and the researchers did see an
expected decrease in the function of the rods and cones, as well as an
increase in cell death. But when the SNP injection was accompanied by an
injection of EGCg, the signs of retinal damage where significantly less.
They concluded that EGCg is a powerful antioxidant that “attenuated the
detrimental influence of SNP to retinal photoreceptors.”
Although we’re not suggesting that you start
injecting green tea into your eyeballs (!), we do think this is another
interesting piece of evidence that demonstrates green tea’s formidable
free radical-quenching abilities and its potential for warding off
disease.
Footnote:
1Zhang
B, Osborne NN. Oxidative-induced retinal degeneration is attenuated by
epigallocatechin gallate. Brain Res 2006;1124(1):176-87.
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com, the most
comprehensive collection of scientific information describing the
health benefits of green tea.
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