10 Green Tea Side Effects You May Not Know

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Green tea is made from Camellia sinensis leaves with some well-known benefits such as against cancer, remove toxins, and relieve stress, against aging. Many people consider green tea an indispensable drink; even some are addicted to this type of drink.


However is green tea absolute safe? Do you wonder that if the more green tea you drink, the more benefits you get? The answer is no. Although this type of tea helps to eliminate toxins, drinking too much it brings many troubles.

Read the whole post to know clearly.

10 disadvantages of green tea you may not know

#1. Leading to insomnia

Do you realize that drinking green tea helps to keep you alert and if you drink green tea in the evening you will have trouble sleeping? This is entirely due to the amount of caffeine in the tea.

Although green tea is not as high in caffeine as coffee, if you drink 4-5 cups of tea per day, the amount of caffeine is not small. A cup of green tea contains about 24-45 milligrams of caffeine while the maximum amount of caffeine you should use per day is 200 milligrams.

#2. Disturbing the mind when drinking green tea too much for a day

It contains a lot of antioxidants, which helps your body maintain healthy and youthful, but that does not mean the more green tea you drink, the better you’ll be.

If you drink too much green tea per day, excessive caffeine intake can lead to disorders in the secretion of hormones in the glands of the body. This can put you in a serious mood disorder, including anxiety and mood swings.
You should only drink no more than 2-3 cups of green tea a day.


#3. Causing gastrointestinal toxicity

Drinking tea when starving makes the kidney function excessively as it leads to urinary symptoms, dizziness, heart arrhythmias, shaking legs, irritation of the gastric mucosa, suppresses the secretion of secretion. This makes us feel uncomfortable, reeling like a "drunk tea". Therefore, don’t drink tea when the stomach is empty.

#4. Increasing the amount of acid in the stomach

Green tea can aggravate the condition of peptic ulcer and increase the acid in the stomach if taken before meals. It can cause abdominal pain, constipation and nausea. So, it is best to drink green tea after a meal.

Drinking too hot green tea will damage the inner wall of the stomach, which leads to stomach ulcers. Although a good cup of green tea has to be brewed from boiling water, the ideal temperature for you to drink green tea is about 45 to 50 degrees Celsius. On the other hand, drinking cold tea is also not good because cold temperatures cause accumulation of phlegm in the mouth.

#5. Causing anemia

When you have anemia or iron deficiency, it is important that you need to reduce the rate of iron absorption in the intestines. However, in fact, in green tea there are some compounds like caffeine, tannin, polyphenols, which can reduce iron absorption in the intestines. That's why it is thought that people should stop drinking green tea when they are anemic.

If you drink green tea much, you should eat foods rich in iron and vitamin C to help prevent anemia. In addition, women during menstruation should not drink green tea because drinking green tea at this stage will cause women to lose more blood. Green tea stimulates the phenomenon of menorrhagia, abdominal pain, which are not beneficial to the body of a woman.

Should anemic people drink green tea?

In fact, green tea only reduces iron absorption when taken during or as soon as eating foods rich in iron or iron supplements. Therefore, people with anemia, iron deficiency can still drink green tea like others. This does not cause any serious consequences.


#1. Reducing the effectiveness of the drug

Normally green tea is a purifying beverage that is good for health but with an anti-cancer drug called bortezomib - it is capable of "beating" cancer cells, green tea is a refined drink of the drug.

Tannin In green tea makes many drugs lose effect. Medications that contain iron when taken with tea will not work. Drinking green tea and taking medicines at the same time may cause hormonal and antibiotic stimulation in your body. This not only reduces the effect of the drug but also can be dangerous to the liver.


#2. Increasing the risk of miscarriage

This danger is also related to the amount of caffeine in green tea. Average caffeine intake may not reduce women's ability to conceive. Most studies have found that consuming less than 300mg of caffeine per day does not affect fertility.

However, some studies have shown a link between high caffeine levels (about 500mg per day or higher) and the rate of reducing fertility.

#3. Bad effects on little kids

So far, the results of the study have not yet agreed on whether caffeine affects babies. However, infants of pregnant women who drink more than 500mg of caffeine per day are more likely to have quick breathing, tachycardia, or sleep deprivation during the first few days of life.

The reason is a small amount of caffeine is secreted into breast milk. So, breastfeeding women should limit caffeine intake. Infants of mothers who drink 2-3 cups of coffee a day can become irritated or have trouble sleeping.

#4. Stimulating constipation in children

Although iron is the primary "ingredient" for blood formation, children under 3 should not drink green tea. Green tea contains phenol that has the effect of gastric and intestinal lining.

This effect will be extremely beneficial to those who want to lose weight but extremely disadvantage to people with constipation due to the constriction of the stomach and intestinal tract will cause indigestion, which makes the constipation worse.

#5. Staining teeth

Tannin in green tea when combined with albumin and caffeine forms insoluble matter. When you drink a lot of tea, it will stick to the teeth and stain your teeth.

The following subjects should not drink green tea regularly

  • People with heart disease and high blood pressure
  • Pregnant women and lactating women
  • Children under 3 years old.
  • People with calcium deficiency and osteoporosis;
  • People with a nervous breakdown;
  • Insomnia;
  • People with glaucoma;
  • People with urinary tract stones;
  • People with liver disease or liver damage


Every healthy food will be good for you only if you use it in right way. Green tea is not an exception.

Those are some side effects of green tea you should know to avoid. You may be anxious after reading the whole post, but do not worry, it only occurs when you drink too much or drink this type of tea incorrectly such as infusing tea too condensed or letting its leaves soak in hot water for too long.

However, we cannot deny the benefits of green tea. Treat yourself with a cup of green tea every day to have a healthy body and sound mind. Thank you for reading the entire post, any comments can be left below. Wish you healthy and happy!


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