Compounds in Green Tea May Protect Against Common Eye Diseases

Green tea has increasingly become one of the world’s most popular beverages, and for good reason. The purported health benefits of green tea are nothing short of amazing. It appears to reduce the risk for a wide range of diseases, from bacterial or viral infections to chronic degenerative conditions including cardiovascular disease, stroke, cancer, diabetes mellitus, rheumatoid arthritis, osteoporosis, and periodontal disease. Green tea can also be used as a weight loss tool when used alongside a healthy diet. Researchers in Japan have found that drinking five cups of green tea a day can burn up to 70 to 80 calories, which translates to about seven pounds a year. And recently, researchers at the Chinese University in Hong Kong discovered yet another benefit of drinking this health-promoting brew—it could protect against common eye diseases such as glaucoma.

For their study, published in the current issue of the Journal of Agricultural and Food Chemistry, Chi Pui Pang and colleagues gave laboratory rats green tea extract and then analyzed their eye tissue. The researchers found that different parts of the eye absorbed varying amounts of catechins, antioxidants which are believed to prevent damage caused by oxidation. The retina, the part of the eye responsible for sensing light, had the highest concentration of the antioxidants, while the least amount was found in the cornea, the clear outer layer of the eye. The antioxidant activity lasted for up to 20 hours after consumption of green tea extract. “Our results indicate that green tea consumption could benefit the eye against oxidative stress,” the authors concluded. Oxidative stress leads to retinal diseases like glaucoma and age-related macular degeneration (AMD).

Green tea is the least processed, made by briefly steaming the just harvested leaves, rendering them soft and pliable and preventing them from fermenting or changing color. After steaming, the leaves are rolled, then spread out and dried with hot air or pan-fried in a wok until crisp. Because of green tea’s minimal processing, its catechins, especially epigallocatechin-3-gallate (EGCG), which is believed to be responsible for most of the health benefits linked to green tea, are more concentrated. It wasn’t known until now, however, if the catechins were able to make their way from the mouth, through the gastrointestinal system, and be absorbed into the tissues of the eye. More studies will be needed to confirm the protective effect in humans.

Adding green tea to your diet is simple and inexpensive. It also provides a healthful alternative to sugar-and-chemical laden soft drinks which are helping to fuel soaring rates of diabetes and obesity.