Side Effects or Warnings of Consuming Excessive Green Tea

Side Effects or Warnings of Consuming Excessive Green Tea:

Black, green, and oolong tea are all derived from the leaves of the Camellia sinensis plant. Fresh leaves from the plant are steamed to produce green tea, while the leaves of oolong and black tea involve fermentation.

Originally cultivated in East Asia, Camellia sinensis grows as large as a tree or shrub. Today, this plant grows throughout Asia and parts of Africa and the Middle East.

Green Tea Side Effects

Liver problemsLiver

There have been some case reports of liver problems in people taking concentrated green tea extracts. The active ingredients in the tea are a class of compounds called catechins.

Catechins target mitochondria, the powerhouses of your cells, and prevent them from being able to help your body metabolize nutrients and turn it into energy, which can lead to hepatitis, jaundice, or liver failure.

Contains caffeine

One cup of tea contains around 24 to 45 mg of caffeine. Too much caffeine can cause the following side effects: nervousness, headache, vomiting, sleep problems, diarrhea,  irregular heartbeat, heartburn, irritability, tremors, ringing in the ears, dizziness, convulsions, or confusion.

Caffeine overdose is possible, with symptoms of abdominal spasms, headache, nausea, and vomiting. It also has a diuretic effect, so you eliminate more fluids through your urine and may become dehydrated.

Contains tannin

This substance is found in any tea that contains leaves from the Camellia Sinensis plant, which means most rooibos and herbal teas don’t have it. Consumption of tannins slows the absorption of important minerals, such as calcium and zinc.

In addition, tannins may interfere with the absorption of nonheme iron, which is the type of iron found in plant-based foods. If your iron level is low, you may want to talk to your healthcare specialist about your tannin intake if you’re a big tea drinker.

During pregnancy and lactation

Green tea contains catechins, caffeine, and tannic acids. All three compounds have been associated with pregnancy risks. No more than two cups of green tea should be consumed during this time.

Completely avoiding this type of tea would be the best option. Caffeine is also a compound that crosses the placenta, and the latest studies suggest that it may decrease blood flow to the developing baby. Additionally, because it’s a diuretic, caffeine consumption can cause the body to release more water than usual.

This means you’ll be urinating more than you already are. For lactating women, the caffeine in the tea can pass into breast milk and affect the nursing infant.

Iron absorption

The catechins present in green tea decrease the absorption of iron from food, which may ultimately lead to anemia. Studies have shown that excessive consumption of this tea may reduce absorption by up to 25%.


It is a condition characterized by a decrease in the density of bone structure, decreasing its strength and resulting in fragile bones.

Women are 4 times more likely than men to develop this condition because of a decrease in their estrogen levels after menopause in conjunction with lighter and thinner bones.

Drinking tea regularly can increase the quantity of calcium that is commonly flushed out inside urine, leading to calcium deficiency.

Digestive problems

The tannins present in the leaves can cause constipation and nausea by producing more gastric acid. Also, the caffeine content in the tea can harm your stomach and intestines by irritating their linings.

Note – excess caffeine intake can also result in overstimulation of the electrical activity of the heart and the nervous system.

Anticoagulant drugs

This tea contains small amounts of vitamin K (approximately 0.03 micrograms per 100 gr of brewed tea), which can make anticoagulant drugs, such as warfarin, less effective.


The combination of tea and chemotherapy medications, particularly tamoxifen and doxorubicin, increased the effectiveness of these medications in laboratory tests. However, the same results have not been found in studies on people.

On the other hand, there have been reports of both black and green tea extracts affecting a gene in prostate cancer cells that can make them less sensitive to chemotherapy drugs. For that reason, people should talk to their physician before drinking tea or taking tea extracts while undergoing chemotherapy.

Long-term consumption may give rise to problems such as headaches, insomnia, hypertension, restlessness, annoyance, abnormal heartbeat, loss of appetite, spasms, constipation, irritability, and acute addiction to caffeine.

Furthermore, green tea consumption can make anxiety worse. So, individuals with anxiety disorders must stay away from it.


In most cases, 1 or 2 cups a day isn’t cause for worry, but if you’re supplementing your 4 coffees a day with double the herbal tea, you may be entering unhealthy territory.


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