Tea is a name given to a lot of brews, but purists consider only green tea, black tea, white tea, oolong tea, and pu-erh tea the real thing.
Regarded for thousands of years in the East as a key to good health, happiness, and wisdom, tea has caught the attention of researchers in the West, who are discovering the many health benefits of different types of teas. Tea is a name given to a lot of brews, but purists consider only green tea, black tea, white tea, oolong tea, and pu-erh tea the real thing. They are all derived from the Camellia sinensis plant, a shrub native to China and India, and contain unique antioxidants called flavonoids. The most potent of these, known as ECGC, may help against free radicals that can contribute to cancer, heart disease, and clogged arteries. All these teas also have caffeine and theanine, which affect the brain and seem to heighten mental alertness. The more processed the tea leaves, usually the less polyphenol content. Polyphenols include flavonoids. Oolong and black teas are oxidized or fermented, so they have lower concentrations of polyphenols than green tea; but their antioxidizing power is still high. Tea contains a large number of potentially bioactive chemicals, including flavonoids, amino acids, vitamins, caffeine and several polysaccharides, and a variety of health effects have been proposed and investigated. It has been suggested that green and black tea may protect against cancer, though the catechins found in green tea are thought to be more effective in preventing certain related cancers such as liver and colorectal while both green and black tea may protect against cardiovascular disease. Numerous recent epidemiological studies have been conducted to investigate the effects of green tea consumption on the incidence of human cancers. These studies suggest significant protective effects of green tea against oral, pharyngeal, esophageal, prostate, digestive, urinary tract, pancreatic, bladder, skin, lung, colon, breast, and liver cancers, and lower risk for cancer metastasis and recurrence.