① Reduce fat and lose weight, and protect cardiovascular and cerebrovascular diseases. Tea polyphenols and their oxidation products in black tea can promote fat dissolution and excretion, and reduce the contents of total cholesterol, free cholesterol, low-density lipoprotein cholesterol and triglyceride in blood, thus reducing cholesterol deposition on arterial wall and reducing the incidence of arteriosclerosis.
② Enhance gastrointestinal function and improve immunity. The effective components of black tea can not only inhibit the growth of harmful microorganisms in human stomach, but also promote the growth and reproduction of beneficial bacteria (such as lactic acid bacteria), which has a good effect on regulating gastrointestinal function. Its alkaloids can promote the secretion of gastric juice, flavanol can significantly enhance gastrointestinal peristalsis, and has obvious effects of relieving depression, stopping diarrhea and relaxing bowels.
③ Lowering blood pressure and blood sugar. Theanine in black tea can inhibit the increase of blood pressure, while alkaloids and flavonoids can relax the wall of blood vessels, increase the effective diameter of blood vessels, and reduce blood pressure by relaxing blood vessels.
Black tea also has some health functions such as cancer prevention, blood lipid reduction, radiation protection and anti-inflammation. Drinking black tea can make people feel comfortable and relaxed, but it won't make people excited and insomnia because of drinking tea.