Search
Language
Green tea What it contains and what doses are safe
Table of Contents
1. What's in green tea?
Green tea leaves contain varying amounts of polyphenols (mainly catechin), caffeine, theanine, teobromine, Theophylline and phenolic acids. The main polyphenol of green tea is epigallocatechin galusan (EGCG). One cup of 250 ml contains 50100 mg EGCG. The caffeine content ranges between 2240 mg per cup. As long as the infusion of the leaves in moderate amounts is safe for healthy adults, green tea extract supplements should be taken with caution.2. Green tea and iron deficiency
Of course, some components of green tea can make it difficult to absorb this element in the intestines. It happens that regularly drinking green tea at high doses can lead to anemia, as in the case described in our diet in 2016. At the time of this study, Clinical Case Reports reported that 48-year-old woman who had a blood transfusion and a type 2 extract of herbal tea could have difficulty absorbing this element into the intestine.3. Green tea and folic acid absorption
Green tea may reduce the bioavailability of folic acid (N. C. Alemdaroglu et al. 2008). Taking 0.4 mg folic acids with 250 ml of green tea reduced the maximum folic-acid concentration in the blood by almost 40% compared to taking the same amount with water. This information is particularly important for pregnant women who are supplementing with folate. During pregnancy, folic and in many cases iron supplementation is necessary. Their absorption may also be disrupted by taking green tea supplements with its extract.4. Green tea and drug metabolism
If we drink green tea and take supplements with its active ingredients, the potential interactions that green tea may have with medicines taken should be taken into account. Animal studies have shown that catechins in green tea can have a significant effect on the action of enzymes involved in drug metabolism. They may inhibit or enhance their action (C. S. Yang et al., 2012). Interactions of green tea with drugs may lead to increased or decreased blood pressure, leading to a risk of an increased concentration of the drug or a weakened antidote.5. Safe doses of green tea
According to a systematic review for an adult with a healthy liver, the safe daily dose of EGCG is 300 mg (equivalent to 36 cups of tea). In the European Union, the average daily consumption of green tea steamed EGCG was 90300 mg (J. Hu et al., 2018). According to EFSA's opinion on the safety of consumption, studies show that taking a daily dose equal to or greater than 800 mg EGCG in the form of a dietary supplement may cause an increase in serum concentration of transplants (liver enzymes) in liver disorders.
