What is Green Tea?
This fact sheet provides basic information about green tea--common names, uses, potential side effects, and resources for more information. All types of tea (green, black, and oolong) are produced from the Camellia sinensis plant using different methods. Fresh leaves from the Camellia sinensis plant are steamed to produce green tea.
Common Names--green tea, Chinese tea, Japanese tea
Latin Names--Camellia sinensis
What It Is Used For
Green tea and green tea extracts, such as its component EGCG, have been used to prevent and treat a variety of cancers, including breast, stomach, and skin cancers.
Green tea and green tea extracts have also been used for improving mental alertness, aiding in weight loss, lowering cholesterol levels, and protecting skin from sun damage.
Green tea could prevent bladder cancer spreading
Green tea can not only lower cholesterol, reduce blood pressure and boost the immune system, it can also help fight cancer.
The health benefits of green tea have been known for a long time: it can lower cholesterol, reduce blood pressure and boost the immune system. Now, it appears, it can also help fight cancer.
Numerous studies, including those involving animals, have shown that green tea not only induces death in cancer cells, but also slows development of the independent blood supply that cancers develop so they can grow and spread.
A recent study demonstrated that green tea extract interrupts a process that is crucial in allowing bladder cancer to become invasive and spread to other areas of the body.
How It Is Used
Green tea is usually brewed and drunk as a beverage. Green tea extracts can be taken in capsules and are sometimes used in skin products.
What the Science Says
Laboratory studies suggest that green tea may help protect against or slow the growth of certain cancers, but studies in people have shown mixed results.
Some evidence suggests that the use of green tea preparations improves mental alertness, most likely because of its caffeine content. There are not enough reliable data to determine whether green tea can aid in weight loss, lower blood cholesterol levels, or protect the skin from sun damage.
Side Effects and Cautions
• Green tea is safe for most adults when used in moderate amount.
• Green tea and green tea extracts contain caffeine. Caffeine can cause insomnia, anxiety, irritability, upset stomach, nausea, diarrhea, or frequent urination in some people. Caffeine can also raise blood pressure, and in very high doses, it can cause seizures, delirium, or irregular heart rhythms.
• Green tea contains small amounts of vitamin K, which can make anticoagulant drugs, such as warfarin, less effective.