The use of green tea is generally safe for adults if consumed in moderation. However, people with stomach problems, iron deficiency and anemia, pregnant women and nursing people, people with blood clotting, heart disease, liver disease and osteoporosis, as well as diabetics should not drink this tea because it may be inconvenient to reflect on their health. The main culprit is caffeine. More than five cups per day are considered excessive tea use, and in people with low caffeine tolerance symptoms, they will also occur after consuming small amounts. They are recommended a maximum of two cups of tea.
Like all teas, green tea contains caffeine, and excessive intake of this substance can cause or worsen the symptoms of stomach ailments such as heartburn or reflux. Because it stimulates the “pumping” of gastric acid, after consuming green tea, pain in the stomach, nausea, and constipation can occur. It is, therefore, best to drink after or between meals. Because caffeine affects muscle contractions, it can hinder the movement of food through the esophagus, and intermittent constriction of muscle relaxation can cause nausea and vomiting.
Iron deficiency and anemia
Green tea reduces the ability to absorb iron from food. The reason for this is caffeine, and this negative effect can be suppressed by adding vitamin C or by extracting half a lemon in the tea.
Psychic and psychosomatic conditions
Caffeine can also cause insomnia, nervousness, and anxiety. Because it blocks chemicals in the brain that control sleep and increases the production of adrenaline. Caffeine can exacerbate tinnitus (buzzing in the ears). And because of the reduced blood flow to the brain causes dizziness and motion sickness.
Green tea stimulates the excretion of calcium in the urine. Which can lead to worsening bone health and osteoporosis. Especially in those that may be predisposed due to other factors.
Pregnancy and heart disease
In addition to caffeine, green tea contains catechins and tannic acids. All three substances are associated with the risks of pregnancy. If you are pregnant or breastfeeding, two cups of tea a day are safe. Caffeine migrates into breast milk and can affect the health of the newborn. In addition, a large amount of tea can cause defects in the neural tube in the baby.