Green tea side effects & health benefits

Green tea side effects

Tea side effects

This article will focus on discussing both potential side effects as well as the positive health benefits of green tea, based on relevant literature and research. While many articles highlight the benefits of tea, there are relatively few that specifically elaborate on its negative effects

Tea has a rich history, evolving from a medicinal drink to a popular beverage over the past 2000 years. Not only does tea provide health benefits, but it also helps in connecting socially. The scientific community has taken an interest in tea due to its widespread use and cultural significance. Research on the physiological effects of green tea has mainly been conducted in lab conditions or using animal models. Green tea’s health benefits are due to compounds such as polyphenols, caffeine, carbohydrates, vitamins, amino acids, and purine alkaloids. While these compounds are generally beneficial for health, it’s important to consume them in appropriate or in limited amounts. The main compounds in green tea include polyphenols, caffeine, and metals like aluminum (1).

Green tea has 30-60mg of caffeine per 6-8 oz. cup, which is less than coffee’s average 100mg. However, weight loss regimes may increase consumption. If 5+ cups are consumed per day, it raises caffeine intake to unsafe levels, increasing the risk for insomnia, restlessness, tremors, and upset stomach (5).

Let us see the side effects of green tea first.

1. Side effects due to Polyphenols and EGCG in tea

Although compounds like Polyphenols and EGCG are good for the body if taken in a controlled amount. Excessive drinking of green tea causes some serious side effects due to the presence of Polyphenol (Catechin) and epigallocatechin-3-gallate (EGCG).

Especially for people suffering from anemia, heart disease, and indigestion problems. Following are the 11 main side effects of taking tea in excess

a. Blocks iron absorption in the body

Iron deficiency anemia is common globally, caused by chronic blood loss and insufficient iron intake or absorption from food. Research shows that iron absorption can be hindered by tea consumption. This is due to the iron-binding properties of phenolic compounds with catechol groups in tea (2).

b. Disturbs RBC formation because of improper folate function

Tea polyphenol, epigallocatechin-3-gallate, is an efficient inhibitor of human dihydrofolate reductase. This disturbs the RBC formation by inhibiting the folate formation (3).

c. Causes Anaemia

Green tea hinders folate formation thus affecting RBC production which eventually leads to anemia.

d. Tooth staining

The components present in green tea like polyphenols cause tooth staining. Thus excessive drinking of green tea results in discoloration of the teen (4).

e. Dehydration

One of the properties of green tea is that it is a natural diuretic. Hence drinking too much green tea around 5-6 cups a day causes excessive urination which ultimately results in dehydration, headache, lethargy, and distress, or sometimes may change in heart rate.

f. Effects on medication

Green tea causes a positive or negative effect on medication depending upon the type of medicine you are taking. According to the reports of The University of Maryland Medical Center, medications such as MAOI inhibitors, lithium, adenosine, and blood thinners can be affected by green tea.

2. Green tea side effects due to caffeine

Caffeine is one of the main ingredients of green tea which has both positive and negative side effects. Although the normal amount helps in keeping the body energetic and stress-free. However the excess amount of caffeine results in insomnia, restlessness, and other types of problems. Following are in short the health benefits and side effects of caffeine

a. Stimulation of the nervous system

Consuming too much green tea (5-6 cups a day) with caffeine can overstimulate the central nervous system and cause symptoms like dizziness, trouble sleeping, shaking, restlessness, difficulty focusing irritability, and hyperactivity.

b. Heart-related issues

Caffeine also causes hypertension, tachycardia, and heart rate irregularities.

c. Other side effects

Excessive intake of green tea also causes sleep deprivation, Restlessness, vomiting, epigastric pain, tremors, palpitations, diarrhea, etc.

3. Side Effects of green tea due to metals

Some metals like arsenic, cobalt, nickel, etc present in green tea although they are in very small amounts excessive consumption may cause dental fluorosis; Due to arsenic’s increased carcinogenic risk.

Consuming 1-2 cups of green tea per day is generally considered safe and may provide many health benefits. Due to being rich in antioxidants, particularly catechins, which help in protecting against cell damage. Also reduces the risk of chronic diseases like heart disease, diabetes, and cancer. Lowers the risk of developing certain neurological conditions, such as Alzheimer’s and Parkinson’s disease. Some of the health benefits of green tea are as follows

Green tea health benefits due to Polyphenols and Caffeine

1. Tea helps in reducing the blood lipid

Green tea or tea helps in the reduction of blood cholesterol and lipids thus strengthening the heart and making the body more active. Therefore drinking tea may help in providing a good healthy heart and active body.

2. Antimicrobial properties of green tea

The secondary metabolites that are present in the tea have antimicrobial properties. Hence helps in fighting against many microbial diseases. It at least gives a certain amount of relief when consumed.

3. Rich antioxidant activity of tea

Of course, everybody is very familiar with the fact of its antioxidant nature. Tea consumption helps in minimizing the free radical activity of the body and thus acts as an antioxidant.

4. Anticancerogenic properties of tea

Again tea contains many secondary metabolites that help in protecting the DNA from damage. It controls the free radicals in the body and unwanted DNA damage.

5. Drinking tea enhances digestion

Green tea helps in solving the digestion problem. It is also advisable by some dieticians that drinking jasmine green tea before bed helps in digestion and thus gives a relaxing sleep.

6. Tea helps in weight loss

The secondary metabolite that is catechins helps in the burning of extra cholesterol and fat resulting in weight reduction.

7. Protecting skin damage

The components present in the tea, like EGCG and catechins, are also helped in protecting the skin. These compounds help in breaking the free radicals present in the cell and thus protect from cell damage and skin abnormalities.

8. Reduce the risk of Alzheimer’s and dementia

Caffeine present in green tea helps in reducing neurological disorders like Alzheimer’s and dementia.

9. Reduce Stroke and Type 2 diabetes

Green tea helps in reducing stroke risk and also controls type 2 diabetes due the caffeine.

4. Instant energy

Green tea acts as an energy booster. The caffeine in green tea provides instant energy, therefore, having green tea helps in relieving tiredness.


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