Black tea is classified as a fermented tea due to its manufacturing process, and there is a misconception that tea catechins are oxidized and lose their antioxidant properties. It is true that black tea has a weak ability to prevent oxidation of oils and other substances in the outside world, but on the other hand, there is a paper that says that the theaflavins in black tea are stronger than unoxidized catechins when measuring the antioxidant properties of active oxygen in the body, although there are differences depending on the measurement method. Thearubigins extracted from black tea at the level consumed in Japan also have the same potency as theaflavins. Recent medical research has shown that while the function of oxygen through breathing is the basis of energy, at the same time, the unavoidable traces of active oxygen that are produced cause deterioration of cell tissue and peroxidation of lipids in the blood.
At this time, enzymes that eliminate active oxygen act as a biological defense mechanism, but the production of excessive active oxygen must be countered by antioxidant substances in food and drink. This is why the intake of antioxidant vitamins such as vitamins A, C, and E, as well as fruits and green and yellow vegetables, is recommended. Green tea catechins and black tea polyphenols are also important antioxidant substances in the body for us. Drinking tea can eliminate active oxygen and free radicals in the body, and is therefore expected to be effective in preventing lifestyle-related diseases caused by them (such as cancer, high blood pressure, stroke, heart disease, and diabetes, which were previously known as adult diseases), inhibiting aging (for example, preventing the appearance of age spots and preventing the fragility of body tissues such as blood vessels), and preventing the production of melanin pigment, among other beauty benefits. Many nutritional supplement tablets containing substances with antioxidant properties have already been released in the United States, and the word “antioxidant” has quickly become associated with the image of being good for health, and the black tea industry is also focusing its promotion efforts on the antioxidant properties of black tea flavonoids.