Black, Green and White teas are made using the dried leaves of the Camellia sinensis bush. The difference in each tea involves the way in which the leaves are processed. Green tea leaves are not oxidized and therefore remain higher in antioxidants and polyphenols, which gives the tea anti-inflammatory properties. The polyphenols in the tea comprise 20 to 45 percent of the dried product's overall weight. Additionally, 60 to 80 percent of the polyphenols contain chemical compounds known as catechins. Cathechins are responsible for the antioxidant characteristics that help prevent cell damage by combating free radicals. Green tea has no calories and only 20 to 45 milligrams of caffeine. As such, many believe that green tea is one of the healthiest beverages in the world.
Preparation and Consumption
Unlike other teas, green tea should not be brewed using boiling water. Elevated temperatures destroy the catechins, which decreases the health benefits. Nutritionists recommend steeping the tea in water ranging from 160 to 170 degrees Fahrenheit. Adding lemon to the tea provides vitamin C and increases the absorption rate of the catechins. On the other hand, adding milk to green tea interferes with absorption of the nutritional compounds. The antioxidant levels of green teas vary from one brand to the next. The more expensive brands have a greater quantity of beneficial chemical compounds compared to less expensive versions. Bottled or canned teas have the least amount of nutritional value.
Proven Cardiovascular Benefits
According to a 2006 article published in the “Journal of the American Medical Association,” the catechins and polyphenols in green tea reduce the risk of developing or dying from cardiovascular disease. The information contained in the article was the result of an 11-year study of more than 40,000 Japanese volunteers who ranged in age from 40 to 79. The participants all reportedly enjoyed a minimum of five cups of green tea daily.
In 2011, a research team published the results of a study performed to evaluate the effects green tea had on cholesterol levels. Individuals consuming four or more cups of the beverage daily experienced a modest reduction in their low-density lipid or bad cholesterol profiles.
In the last decade, studies performed by the University of Michigan and the University of Missouri found that the CATGE catechins in green tea protected neurons in the brain from developing the amyloid-beta proteins that are associated with dementia and Alzheimer's. The researchers believe the chemical compounds play a role in interfering with the processes that cause the proteins to fold and tangle. They reported that drinking green tea and getting regular exercise prevented the progression of Alzheimer's disease in laboratory animals. With further research and testing, the scientists hope that the compounds in green tea might lead to the development of a treatment for Alzheimer's.