Tea is one of the most popular beverages in the world, with some reports stating that tea is second only to water in worldwide beverage consumption. Tea is embedded in culture: The British have tea time, and Asian communities still practice ancient tea ceremonies.
Tea drinkers are onto something.
There are several health benefits of green tea in particular, due largely to the way it is processed. Unlike black and oolong tea leaves, which are fermented, green tea leaves are steamed, leaving a higher concentration of antioxidants, called polyphenols. These antioxidants are why green tea is widely promoted for its health benefits.
Though much research is yet to be done on the impact of green tea on health, widespread studies prove the attention is warranted, said Lauren Kolesa, a registered dietitian based in Morris County, New Jersey. “I think many of us are looking to more natural resources when planning meals and choosing products. The shift seems to be toward more ‘whole’ and ‘natural’ foods,” she said, adding, “Any food or product that touts anti-inflammatory properties seems to generate interest these days.”
Studies have indicated several benefits to green tea, such as:
Drinking green tea can help prevent heart disease. Many studies have looked at the link between green tea and heart health. Some research has shown that the antioxidants in green tea help block the oxidation of “bad” cholesterol (LDL) and increase the “good” (HDL) cholesterol, which helps improve artery function and stave off heart disease.
Green tea may reduce inflammation. Green tea has been shown to calm the body's immune system by stimulating anti-inflammatory responses. Inflammation has been linked to various cancers, diabetes, rheumatoid arthritis, heart conditions and other inflammatory diseases.
Green tea assists in weight loss. Some small studies have shown that drinking green tea — and, in some instances, consuming green tea extract — has helped with moderate weight loss, possibly because of the diuretic properties of green tea and those powerful antioxidants.
The antioxidants in green tea can help protect against certain types of cancer. According to the University of Maryland Medical Center, several clinical studies have shown that both green tea and black tea can help protect, but not necessarily prevent, cancer, as “researchers also believe that polyphenols help kill cancerous cells and stop their progression.” Green tea has the highest impact on cancers including bladder, breast, prostate and skin, according to the University of Maryland medical reference. Studies have been conducted on the impact of green tea on other forms of cancer with conflicting results.
Green tea could play a role in regulating the body’s glucose levels. Studies cited by the University of Maryland Medical Center website found that “daily supplementation…with green tea extract powder lowered the hemoglobin A1c level in individuals with borderline diabetes.”
How do you get the most out of your green tea consumption? The most successful clinical studies on the benefits of green tea suggest it’s best to drink at least three cups per day, freshly brewed. Kolesa said she encourages clients to drink the home-brewed version of green tea rather than bottled brands, which have sugar.
Before considering green tea — or any remedy — for medicinal or health purposes, discuss its benefits with your doctor, Kolesa added. "Green tea can interact with a number of medications."
Editor's note: This story has been updated with new information since it was published in February 2012.