Who benefits from black tea, and who is green?
The main therapeutic effect of tea is provided by alkaloids. This is known to you caffeine and not very famous - theobromine, nophiline, xanthine, hypoxanthine and paraxanthin. The latter are caffeine antagonists. Both are in black and green tea. The alkaloid caffeine provides a tonic effect at first, which is not stable, and soon after the inactivation of caffeine, its antagonists enter the reaction. They reduce the tone of blood vessels and lead to a decrease in blood pressure, which is necessary for hypertonics and unnecessary hypotension. According to this scheme, "green tea" works. Black tea in the second phase due to the high content of vitamins of group B, P and PP, preserved by fermentation, preserves the tone of the vessels and "holds" the pressure. Here it is ideal and suitable hypotonic.
The mechanism of the action of black and green tea is as follows.
Caffeine tea excites the cerebral cortex, dilates blood vessels, improves blood supply and oxygen supply to the brain. Therefore, with the use of tea, the activation of the action of the brain, the removal of a feeling of fatigue and drowsiness are associated. In this case, the headache associated with spasm of cerebral vessels disappears.
Because of the greater caffeine content, a tonic effect is more active in green tea. Black tea acts more gently and continuously, without causing a feeling of dryness in the mouth.
Practical doctors often prescribe green tea to hypotonic patients. However, after the intake of green tea, as a result of the stimulating effect of caffeine, which is in its composition, at first there is an increase in heart rate and respiration. Blood pressure slightly increases, feeling better. Later, as the amount of strong tea drunk, especially the 95th test, increases, people with hypotension tend to develop a feeling of weakness and lower blood pressure. These phenomena Yu N. N. Nuraliev explains the different chemical composition of green and black tea.
In addition to caffeine, as you already know, in addition to caffeine, there are alkaloids such as theobromine, theophylline, xanthine, gopoxanthin, paraxanthin, and also ascorbic and nicotinic acids. All these compounds, except for caffeine, have a vasodilating action, i.e.are physiological caffeine antagonists. Black tea contains many vitamins B, P and PP.From literary sources it is known that vitamin B1 in certain doses increases the tone of blood vessels and can increase blood pressure. Catechins, including vitamin B, increase the tone of the capillaries. After receiving green and black tea, the resulting tonic effect is directly related to the effect of caffeine. However, caffeine is quickly inactivated or removed from the body, and from that moment begins the second stage of tea. That is, if in the first stage of the manifestation of physiological action, both tea behave identically, then in the second stage, after the inactivation of caffeine, their pharmacological effect on blood pressure sharply differs.
After taking hot tea under the influence of vitamin C, theobromine, theophylline and other factors, the tone of the vessels drops. In healthy individuals, this reaction remains unnoticed. For hypertensive patients, a similar effect of green tea is useful, and for hypotensive people, on the contrary, it is very undesirable. In the second stage of the action, black tea is dominated by the pharmacological effect of catechins or vitamins of P-like substances. Raising the tone of the capillaries, they prevent the vasodilating effect of theobromine, theophylline, as well as vitamins C and PP.In addition, in the manifestation of the tonic effect of black tea, a certain role is played by vitamin B).Therefore, black tea, unlike green tea, does not worsen the condition of hypotension.
Analysis of the therapeutic properties of various types of tea confirms the correctness of the position of folk healers who considered green tea useful for hypertensive patients and harmful to people with low blood pressure. That is, it should be stressed again that patients with hypotension or persons who have a tendency to fainting should refrain from taking strong brewed green tea. For them, the highest grades of green tea are absolutely contraindicated.
Contraindications for the reception of green tea are a hyperacid form of gastritis, peptic ulcer of the stomach and duodenum. In such patients, the reception of green tea is accompanied by the occurrence of heartburn, increased pain in the stomach, in some cases - the occurrence of intestinal colic.
Tea is an exciting drink, so you can not drink strongly brewed tea before bed. Nursing mothers should know that part of caffeine is excreted through milk and taking a lot of brewed tea overnight can cause insomnia in infants. Strongly brewed tea is harmful for patients with increased thyroid function( with hyperthyroidism).The excessive intake of tea, especially green tea, causes severe sleep disorders, body exhaustion, palpitations, hand tremors and a number of other negative reactions.