An introduction to Green Tea

Drinking tea is part of the local culture in different Asian countries including Thailand, India, Japan and China. There are different kinds of teas and all of them are produced using the same species of plant called camellia sinensis. The three most common types of tea plants are Assam or Indian, Chinese and the hybrid. These are used in producing the four main types of teas called white, black, oolong and green.

Green tea has an edge over other types of teas. This is because it requires minimal processing which results to more catechins being stored in each bag. It is non-oxidized like white tea. But unlike white tea, it is made with rolled leaves and not with the buds. Green tea has a gassy taste and is low in caffeine but has higher antioxidant content than black and white tea.

According to historical records, China and India were the first countries to cultivate and produce tea. And today, tea has become a part of people's healthy beverage choices. As a matter of fact, tea is second to water as the most consumed beverage in the world. Green tea was first used in Asian cultures to promote the secretion of urine and to heal and control the bleeding of wounds. People also drank tea to promote heart health and to treat flatulence and promote better digestion, regulate blood sugar and body temperature and optimize mental processes.

Antioxidants in Green Tea

Green tea contains numerous types of powerful antioxidants. The polyphenol content of green tea are called catechins. The catechin compounds found in green are apigallocatechin gallate popularly known as EGCG, gallaogatechin, catechin, epicatechin, epicatechin gallate and epigallocatechin. EGCG is the most observed and studied polyphenol content found in green and it has been found to be the strongest and most active. Studies also show that green tea contains alkaloids like theophylline, theobromine and caffeine; these are responsible for the stimulating effects of green tea. The L-theanine content of green tea, on the other hand, has been found to have calming effects on the central nervous system.

Privately-funded and state-subsidized studies have found that green tea has strong antioxidant properties in fighting cancer. A study conducted by a group of researchers from India observed that polyphenols in green tea extract can have the strongest free radical scavenging ability than other known antioxidants.

Green Tea against Free Radicals

A study performed by Indian researchers found that a fraction of green tea extract rich in polyphenols may be the richest and strongest source of antioxidants. They observed that the extract has a remarkable ability to scavenge free radicals. Studies on cancer have linked the dreaded disease to the presence of free radicals in the body.

The study was published in the Journal of Food and Biochemistry and the researchers’ primary goal was to investigate green tea extract's ability to remove free radicals and harmful singlet oxygen molecules from the body. The study was focused on Sunphenon, a fraction of green tea extract that contains around 75 to 80 percent polyphenols. Head researcher Subramanian Kaviarasan, from the University of Annamalia, said that Sunphenon's ability in scavenging free radicals makes it one of the strongest forms of defense against cancer. He added that according to the results of their studies, Sunphenon is also one of the richest sources of free-radical scavenging compounds.

The green tea extract fraction is produced by a private company Taiyo International. The researchers disclaimed that though the products were provided by the company, their research and the results of the study were not influenced in any way by Taiyo International. The study was also partly funded by the Indian Council of Medical Research.

The researchers said that Sunphenon green tea extract is rich in catechins and purified polyphenols. According to other studies, polyphenols have strong antioxidant, fat-burning and anti-microbial properties. The study was aimed at discovering polyphenol's potential in removing free radicals from the body and optimizing a person's defense against cancer. They observed that Sunphenon can improve the body's plasma antioxidant capacity by around 35 to 40 percent an hour after consumption. It has also been observed to decrease the lifetime of singlet oxygen from 64 to 21 microseconds. Sunphenon was also found to protect the cells and the DNA against damage caused by peroxide and radiation.

Other Health Benefits of Green Tea

Cholesterol. Studies show that drinking green tea can lower bad cholesterol and raise good cholesterol levels in the blood. A large scale clinical study showed that men who drink green tea are less likely to have high cholesterol level than other men who are not into the habit. A related study on animals concluded that polyphenols in green tea can help block the absorption of cholesterol in the intestines and help in its secretion from the body.

Diabetes. Studies have found that green tea can help regulate blood sugar levels and help people with type 1 diabetes. Type 1 diabetes occurs when the body produces insufficient insulin to regulate glucose. A study on children also showed that the daily supplementation of green tea extract in children with borderline diabetes can lower blood sugar level.

Weight Loss. Green tea had also been found to help in the burning of fats and promote faster weight loss. Studies found that green tea extract can boost a person's metabolism. Researchers are looking at the catechin content of green tea to be responsible for the fat-burning effect of green tea. A related study confirmed that the combination of caffeine and green tea can be effective in promoting weight loss in overweight and moderately-obese individuals.

Liver Disease. Numerous animal and human studies suggest that the polyphenol catechin found in green tea can help treat viral hepatitis when administered in extremely high dosage. But the question whether drinking green tea can result to the same effect remains. Researchers suggest the use of catechins as a treatment against viral hepatitis while drinking green tea is yet to be studied to discover its effects on the condition.

Sources
nutraingredients.com
wisegeek.com
webmd.com
livestrong.com
umm.edu