Green tea helps prevent certain types of cancer.
WHAT THEY’RE SAYING
Many in the media are claiming that drinking green tea is good for your health. Some say the drink promotes weight loss, reduces stress, lowers high cholesterol levels, boots immunity, inhibits bone loss, improves mental alertness, and even that it helps prevent certain types of cancer. Green tea is high in antioxidants compared to other drinks like sodas, sport drinks, and water. It is also commonly marketed as a weight loss product.
WHAT WE KNOW
Tea is the most consumed beverage in the world after water and has been in use for over 500 years. All types of tea (white, green, black, and oolong) are produced from the plant Camellia sinensis using different methods. Green tea is usually brewed and drunk as a beverage; however, green tea extracts can be taken in capsules and are sometimes used in skin products. Many of the benefits of green tea in particular have been attributed to the amount of antioxidants found in the tea leaves. These substances are also present in other plant foods like fruits and vegetables.
Green tea is safe for most adults when used in moderate amounts but it does contain caffeine. Caffeine can cause insomnia, anxiety, irritability, upset stomach, nausea, diarrhea, or frequent urination in some people. Green tea also contains small amounts of vitamin K, which can make anticoagulant drugs, such as warfarin, less effective.
HOW DO WE KNOW THIS?
The effect of green tea consumption on cancer risk has been the focus of numerous studies. More than 100 epidemiological studies have examined the effect of tea consumption on cancer risk and research in animals. These studies consistently show that consumption of green tea reduces the risk of various types of cancers. 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, boost immunity, or lower blood cholesterol levels. A new study by researchers from the Chinese University of Hong Kong have found that three metabolites in green tea can stimulate bone formation in rats and help slow the breakdown of their bones. However, a U.S. study on mice suggests that green tea may actually weaken bones. According to the researchers, it’s not clear whether similar effects occur in humans.
Similar antioxidant benefits can be obtained from eating a great variety of fruits and vegetables but if you enjoy green tea, continue to drink it in moderation. Just be skeptical whenever any one food or drink seems too good to be true, and you should not rely on one type of food or drink exclusively to improve your health.