Green Tea Could Protect Eyes From Glaucoma

By Margarita Nahapetyan

Green tea may help protect the eyes from glaucoma and fight other eye diseases, claim scientists from Hong Kong, who found that substances responsible for many of the health benefits of green tea work their way into the tissues of the eye and have antioxidant activity there.

Glaucoma is a disease of the eye in which damage is caused by high pressure inside the eye. The condition leads to the optic nerve damage and gradual loss of vision. According to Chi Pui Pang and colleagues from the department of ophthalmology and visual sciences at the Chinese University of Hong Kong, catechins are among a number of antioxidants, including vitamin C, vitamin E, lutein, and zeaxanthin, that are believed to help protect the delicate tissues of the eye from glaucoma and other eye conditions. Until now, however, nobody knew if the catechins in green tea could actually pass from the stomach and gastrointestinal tract and penetrate into the tissues of the eye.

In the study, scientists fed laboratory rats green tea extract and then examined their eye tissues. When they analyzed the cornea, lens, retina, choroid-sclera, vitreous humor, and aqueous humor, they discovered that these various eye structures had absorbed varying amounts of individual catechins. For instance, the area with the highest concentration of gallocatechin was the retina, which is the light-sensing tissue that is located in the back of the eye, and the area with the least absorption of catechins was the cornea, which is the clear, outer layer of the eye. The aqueous humor absorbed epigallocatechin. The study also demonstrated that the time of maximum concentration of the catechins differed from 0.5 to 12.2 hours and the effects of green tea catechins in reducing harmful oxidative stress in the eye lasted for up to 20 hours after drinking.

According to the researcher Kai On Chu of the department of ophthalmology and visual sciences at the Chinese University of Hong Kong, the new findings suggest that drinking green tea could be protective of the eyes in general. The scientists concluded that "green tea consumption could benefit the eye against oxidative stress." However, more research will be needed in order to confirm a protective effect of green tea in humans.

Green tea, the favorite hot drink of people in China, Taiwan, Hong Kong, Japan and Middle East, is referred to as a health drink, reducing the risk of a number of conditions and assuring a healthy life. Green tea is believed to be beneficial for reducing the risk of certain cancers, high cholesterol levels, cardiovascular disease, rheumatoid arthritis, impaired immune function, depression and infection.ADNFCR-2035-ID-19630159-ADNFCR In addition, drinking green tea does play a significant role in preventing tooth decay. While on one hand its ability to destroy bacteria can help avoid food poisoning, it can also kill the bacteria that build up dental plaque.

The findings are published in the current issue of the American Chemical Society's Journal of Agricultural and Food Chemistry.