The leaves of Camellia sinensis are rich in flavonols or catechins that provide antioxidants far more powerful than your everyday vitamins A, C, and E.
Unlike black tea (made from the same tea leaves but fermented), green tea comes from mature leaves that are steamed or fired. Unfermented tea contains between 30 and 42 percent of catechins.
All teas have caffeine. Green tea contains about half the caffeine in coffee. Black, green, and oolong teas also have levels of fluoride comparable to levels recommended for preventing dental cavities.
Drink to Your Health
Consumed for centuries as a tonic in numerous cultures, green tea lowers mortality. Small clinical studies find that this unfermented tea can help you lose and manage weight, lower cholesterol, and control blood sugar. No wonder that epidemiological research suggests that green tea helps prevent cardiovascular disease and stroke.
A good deal of recent attention has focused on this tea’s impact on body composition, particularly the visceral fat implicated in heart disease. Small, cumulative effects on metabolism (amounting to as little as 3 to 4 percent more energy expenditure) from green tea can create longer-term effects on body composition. In one study, habitual tea drinkers (the vast majority of whom drank unfermented tea) had almost 20 percent less body fat than those who drank other beverages.
Green tea consumption has long been associated with cancer prevention. While some of the evidence is inconclusive, regularly drinking unfermented tea appears useful in fighting breast and prostate cancers. Researchers at the University of Alabama at Birmingham conclude that catechins in green tea may halt the growth of estrogen-receptor negative breast cancer cells—the type that spreads fast and is hard to treat.
Research at Temple University School of Dentistry compared tea drinking to juice and soda consumption and found that tea did not erode tooth enamel any more than water.
Safety and Contraindications
Even when drunk in large quantities, green tea is considered safe. However, some experts warn pregnant women to limit their caffeine consumption to 300 milligrams a day.
Excessive amounts of unfermented tea may weaken the therapeutic effects of the anticoagulant drug warfarin, but it’s probably not necessary for anyone taking this medicine to give up drinking green tea entirely. New research also finds that green tea extract can weaken the antibacterial effect of amoxicillin on the superbug methicillin-resistant Staphylococcus aurea in mice.
“Green tea seems to be a low-risk complementary therapy for a number of conditions,” conclude researchers at Maine Medical Center.
What’s Your Favorite Green?
Cultivation of tea plants dates back thousands of years, and different countries have developed different types of green tea. Today China produces more than half the green tea available to consumers. Dragon Well is that nation’s most popular tea. Jade Spring is somewhat sweet and can be resteeped without tasting bitter. Gunpowder Green Tea is the most popular Chinese tea in the West.
Almost all the tea produced in Japan is green. Bancha has a yellowish tint with a full and refreshing flavor. Sencha is the most common Japanese green tea. And Matcha is prized in traditional Japanese tea ceremonies, dating back to the 1200s when monks used it as an aid to meditation.