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.
We know tea is a healthy beverage choice, but there are several health benefits of green tea in particular, due largely to the way it's 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.
There's a growing body of research on the impact of green tea on health, and 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, including:
1. Tea drinkers live longer.
Researchers tracked about 100,000 people via questionnaires. They had no history of heart attack, stroke or cancer. They were all participants in a project called China-PAR, or Prediction for ASCVD Risk in China that has covered 15 provinces across China since 1998. Those who maintained a consistent habit of drinking tea, and especially green tea, showed a reduced risk of cardiovascular disease associated with plaque buildup and a reduces risk from all causes of death. The study, published in the European Journal of Preventive Cardiology, boiled down the results to a simple habit: drinking tea at least three times a week.
"The protective effects of tea were most pronounced among the consistent habitual tea drinking group. Mechanism studies have suggested that the main bioactive compounds in tea, namely polyphenols, are not stored in the body long-term. Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect," senior author Dr. Dongfeng Gu, Chinese Academy of Medical Sciences, told EurekAlert!
2. Drinking green tea can balance cholesterol levels.
Several studies have looked at the link between green tea and heart health, according to Harvard 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.
3. Green tea may reduce inflammation.
Green tea contains powerful antioxidants called catechins, which have been shown to calm the body's immune system by stimulating anti-inflammatory responses, according to a study published in BioMed Research International. Inflammation has been linked to various cancers, diabetes, rheumatoid arthritis, heart conditions and other inflammatory diseases.
4. Green tea may assist in weight loss.
Some small studies have shown that drinking green tea — and, in some instances, consuming green tea extract — has helped with body weight regulation, according to a study published in the journal Physiology & Behavior, possibly because it contains caffeine and catechins, which may improve the body's fat oxidation process.
5. The antioxidants in green tea can help protect against certain types of cancer.
Several clinical studies have shown that both green tea and black tea can help protect, but not necessarily prevent, cancer, according to the University of Maryland Medical Center, which added in its green tea overview that "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 research. Studies have been conducted on the impact of green tea on other forms of cancer with conflicting results.
6. Green tea could also play a role in regulating the body's glucose levels.
Additional studies cited by the University of Maryland Medical Center overview 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 home-brewed green tea rather than bottled brands, which often include 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 since it was published in February 2012.