Green Tea: The Eyes Have It
Eyes Can Absorb Antioxidants From Green Tea, Which May Have a Protective Effect, Researchers Say
Feb. 18, 2010 -- Researchers say the compounds responsible for many of the
health benefits of green tea are capable of penetrating the tissues of the eyes
and have antioxidant activity there.
Green tea has been touted for a number of health benefits, such as fighting
heart disease and cancer, thanks to its high concentration of disease-fighting
antioxidants called catechins.
Researchers say catechins are among a number of antioxidants, including
vitamin C, vitamin E, lutein, and zeaxanthin, thought to help protect the
delicate tissues of the eye from glaucoma and other eye diseases. But until now
it wasn't known if the catechins in green tea were capable of being absorbed
into the tissues of the eye.
Another Health Benefit of Green Tea
In the study, published in the Journal of Agricultural and Food
Chemistry, researchers fed laboratory rats green tea extract and then
analyzed their eye tissues.
The results showed that different parts of the eye absorbed varying amounts
of catechins. The area with the highest concentration of catechins was the
retina, which is the light-sensing tissue that lines the back of the eye. The
area with the least absorption of catechins was the cornea, which is the clear,
outer layer of the eye.
The study also showed that a
measure of antioxidant activity lasted for up to 20 hours after the drinking
green tea extract.
Researcher Kai On Chu of the department of ophthalmology and visual sciences
at the Chinese University of Hong Kong and colleagues say that their findings
suggest that drinking green tea could be protective of the eyes. Further
studies, however, will be needed to confirm a protective effect in humans.