Tea: A traditional but always modern beverage. Do you know how beneficial it is?

Dimitris Papadopoulos MD Fellow Of Interventional Pain Practice (FIPP)

Updated 18 June, 2011

Tea has been known for centuries now. The Chinese were the first to use it both as a medicine and a drink in social events. In Europe it became known in the 16th century. In 1650 it was introduced for the first time in Britain and was adopted mainly by the upper social classes. It is the second most widely consumed beverage in the world, after water, and it clearly prevails to coffee, beer, wine and soft drinks. Tea is produced from the dried leaves, branches and leaf buds of the Camellia Sinensis bush, which are soaked into hot water for a few minutes. After being collected, they get immediately dried, so that their oxidation process is discontinued. This is done to avoid  the degradation of the great many polyphenols they contain. There are 4 types of tea, depending on the degree of leaf drying processing:

  • White tea, originating from young buds of the plant that have not undergone any oxidation. It is produced in smaller quantities than the rest of tea varieties and that is why it is more expensive and more rarely consumed.
  • Green tea, originating from leaves that have undergone minimal oxidation
  • Black tea, whose leaves have undergone significant oxidation under controlled temperature and moisture conditions. This processing causes enzymic reactions resulting in the change of the color of leaves.
  • Oolong tea, whose leaves have undergone partial oxidation, somewhere between that of the green and black tea.

Tea contains a great number of polyphenols (antioxidants) that are called flavonoids. The main flavonoids contained in the Camellia sinensis plant are the so-called catechins. During the black tea processing, catechins polymerise into theaflavins and thearubigins. So, the green tea is rich in catechins while the black tea is rich in catechin  polymers. Many studies have demonstrated the highly significant antioxidative action of flavonoids. More specifically, it has been found that the antioxidative effect of 2 cups of tea equals to that of 4 apples or 7 glasses of orange juice. Of course, this depends on the bioavailability of flavonoids, as well as to the degree of body metabolism and distribution to tissues.
There are also other highly interesting positive effects of flavonoids in the human body. Tea consumption has been correlated with reduction of cardiovascular diseases, while experimental data confirm the angio-protective, anti-thrombotic, anti-inflammatory and hypolipidaemic properties of flavonoids. Hence, the interest of clinical studies focuses on the effect of flavonoids on endothelial function, reduction of total and LDL cholesterol and inhibition of blood platelet adhesion. It seems that consuming 3 cups of tea daily can reduce infarction risk by 11%.

Some researchers have also demonstrated that polyphenols, as antioxidants, protect the DNA gene structure from oxidative damage involving chromosome fragmentation and mutations. Consuming food containing high concentration of polyphenols, such as tea, can reduce the risk for malignant neoplasias and particularly colorectal cancer. Other scientists all over the world have been investigating the degree to which tea consumption contributes to body hydration. They studied the above hypothesis under various conditions and in various combinations. The results are positive because it has been found that moderate tea consumption –about 4 to 6 cups of tea daily- contributes to maintaining homeostasis of body fluids and giving the feeling of well-being and spiritual calmness. As for those supporting that tea consumption increases caffeine consumption, researchers have shown that moderate tea consumption does not contain any health risk. Finally, it has been found that consuming tea in combination with 6 to 8 glasses of water has a synergistic effect with regard to body hydration.

To sum up, it has to be pointed out that tea is an excellent choice for promoting and maintaining health, always in combination with a well-balanced diet. It undoubtedly offers a very good alternative to avoid consuming other beverages, soft drinks and high energy drinks.