February 22, 2010
By Philip Hogan
Substances found in green tea could help fight eye disease, according to authors of the latest research from the University of Hong Kong.
Scientists from the department of Ophthalmology and Visual Sciences at the University of Hong Kong have confirmed that substances found in green tea do penetrate into the tissues of the eye, a fact previously unknown as scientists were unsure if catechins, which are antioxidants thought to protect the body against damage from oxygen, could make their way from the mouth to the gastrointestinal system to the eyes.
The article, which is featured in the Journal of Agricultural and Food Chemistry, is the first of its kind to document how the lens, retina and other tissues within the eyes absorb beneficial substances such as catechins. The research within the study raises the possibility that among green tea’s long list of already documented health benefits that it might also help to protect against common eye diseases such as glaucoma.
Catechins contained within green tea, as well as other antioxidants such as vitamin C and E, lutein and zeaxanthin have long been linked with having the capability of protecting the eye from disease, but lack of research has, until now, left this thought unproven.
The study was conducted using laboratory rats that were fed green tea over a period of time. Subsequent dissection and analysis of the rats’ eye tissue showed significant absorption of individual catechins into various structures of the eye. The retina was seen to absorb the highest levels of gallocatechin, with the aqueous humor absorbing epigallocatechin.
The authors of the research stated that their ‘results indicate that green tea consumption could benefit the eye against oxidative stress’. The effect of the green tea catechins on the laboratory rats was a reduction in harmful oxidative stress in the eye, which lasted up to twenty hours.