Experts advise reducing tea consumption during medication and, more importantly, not taking medicine with tea, as tea can diminish the effectiveness of the medication.
First, let's understand what tea is. The composition of tea is very complex, containing over 450 types of organic compounds and about 15 types of inorganic mineral nutrients. The main organic compounds found in tea that are considered to have a direct relationship with the human body include: tea polyphenols (also known as tannins), alkaloids, proteins, aromatic substances, pectin, and sugars, which are the main soluble components of tea. Deputy Chief Physician Zhai Qingling told reporters that tea can indeed significantly reduce the effectiveness of some drugs, and special attention should be paid to the following four types of drugs:
1. Alkaloid drugs: Tea polyphenols account for about 20% to 25% of the dry weight of tea. Tea polyphenols react with alkaloid drugs such as berberine, ephedrine, and hyoscyamine to form insoluble organic alkaline precipitates, thereby affecting the absorption of these drugs in the body. Common drugs in this category include berberine, ephedrine, and belladonna tablets.
2. Drugs containing metal ions: Tea polyphenols, also known as tannins, are easily broken down into tannic acid in the body. Tannic acid can form insoluble tannic acid compounds with metal ions in drugs, such as forming tannic acid with iron preparations for treating anemia, and forming tannic acid with aluminum hydroxide for treating ulcers.
3. Sedative and tranquilizing drugs: The alkaloids in tea are mainly purine alkaloids, the most abundant of which is caffeine, followed by theobromine and theophylline.
Caffeine and theophylline have a stimulating effect on the central nervous system and can reduce the sedative effect of benzodiazepines (such as diazepam) and barbiturates.
4. Tonic Chinese medicines: The saponins and alkaloids contained in tonics will combine with tea polyphenols to form precipitates that cannot be absorbed by the human body, thereby reducing the tonic effect of the supplements. Common tonics such as ginseng, astragalus, fleeceflower root, and prepared rehmannia root contain relatively high levels of alkaloids and other active substances. Therefore, it is not advisable to drink tea while taking tonics, and even less so to use tea as the vehicle to take them.
In addition to the above categories of drugs, there are other medications whose effectiveness can be reduced when taken with tea, such as enzyme preparations (e.g., polyenzyme tablets) and dipyridamole (Persantine). Generally speaking, except for some special medications that require an excipient like alcohol to be taken, it is best to take other medicines with plain water. It is not recommended to use beverages, fruit juices, etc., and it is especially not recommended to take medicine with tea. Furthermore, avoid drinking tea for 2-3 hours before and after taking medication.