Green Tea - Safety Concerns, Precautions and Warnings

Green tea is one of the healthiest drinks on the planet because of its numerous health benefits. Benefits of Green tea includes reduction of genital warts, regulation of cholesterol and resistance to cancer. Consumption of green tea also helps with weight loss, builds immunity, fights diabetes, resists cancer and helps reduce chances of heart-related diseases. (Reference: Green Tea - Health Benefits Uses and Dosage, Teacurry.com, Retrieved on 1 January 2024) It also helps in improving brain function and helps keep us safe from cold and flu. (Reference: Green tea, Wikipedia, Retrieved 1 January 2024) However, in this article, the teacurry.com team has tried to elucidate the safety concerns and side effects of consuming green tea. Below questions have been answered.

1. Are there any safety concerns related to Green Tea?
2. Elucidate the dosing considerations for Green Tea
3. Precautions and warnings of green tea for children and green tea during pregnancy.
4. Precautions and warnings of green tea for patients having medical conditions.

Are there any safety concerns related to Green Tea?

Green tea is very much safe for adults when consumed or applied in below-listed cases (in below-suggested amounts):

• Drinking green tea or consumption of matcha powder in moderate amounts (up to 4 cups a day) on a regular basis.
• Appling green tree extract-based ointment (other ingredients being natural like Veregen) twice a day over the skin. (Reference: Flavonoids: The secret to health benefits of drinking black and green tea?, Harvard Health Publication, Retrieved 1 January 2024)
• Applying used Green tea bags over skin or eyes for beauty purposes.
• Green tea extract consumed through the mouth for up to two years.
• Geen Tea contains little less caffeine than normal tea, so it is preferred to take green tea during pregnancy in limited quantity.
• Green tea extract used as a mouthwash for a suggested short term period (up to six months). (Reference: Green Tea: Health Benefits Uses and Side Effects, RX List, Retrieved 1 January 2024) 

However, it has been found to cause below issues in some set of people:

• Causing stomach upset and constipation
• In some rare cases leading to problems with the liver or the kidney
• Becoming unsafe when taken through the mouth in high doses of the excess of 6 cups a day.
• Leading to side effects because of caffeine (especially matcha green tea) - headache, nervousness, sleep problems, vomiting, diarrhoea, irritability, tremor, convulsion and dizziness.
• Since Green tea has caffeine content, it is preferred to take Green tea during pregnancy in limited cups of up to 2 cups. During pregnancy, green tea taken in excess quantity can have the same side-effect as taking more tea, like nausea, dizziness, sleep problems etc
• Deprive the body's capacity of absorbing iron from food. (Reference: Flavonoids: The secret to health benefits of drinking black and green tea?, Harvard Health Publication, Retrieved 1 January 2024)

Harmful Effects of Drinking Green Tea, Cup and Leaf, Google Images, licensed under CC BY 2.0

A fatal dose of caffeine in the case of green tea is estimated to be a continuous consumption of 10-14 grams. 2g of green tea contains 25 mg of caffeine and is used to prepare around 8 ounces of green tea. Based on the same estimation around 800g of best green tea leaves are needed to be consumed in the form of liquid to reach fatal levels. (Reference: Flavonoids: The secret to health benefits of drinking black and green tea?, Harvard Health Publication, Retrieved 1 January 2024)

How much Green tea should I drink daily?

Based on scientific data collected below are the suggested dosages in case of green tea:

• For people with no medical condition up to 4 cups of green tea on a daily basis is recommended for weight loss purposes.
• Green Tea during pregnancy is considered to be safe when taken in a limited quantity of 2 cups a day.
• For patients with high cholesterol, Green tea or matcha green tea or green tea extracts containing 150 to 2500 mg catechins is recommended. It should be taken in single or two divided doses daily for up to six months. (Reference: EFSA accesses safety of Green tea catechins, European Food Safety Authority, Retrieved on 1 January 2024)
• For patients with abnormal development of cells of the cervix (cervical dysplasia), green tea extract is suggested - the dosage is 200 mg on a daily basis. Also, green tea ointment can be applied twice weekly for up to three months. (Reference: Green tree extract: Pros and Cons for Energy weight loss and more, Cleveland Clinic - Health Essentials, Retrieved on 1 January 2024)
• For patients with high blood pressure green tea (and matcha tea), made by boiling a 3-gram tea bag with 150 mL of water - should be consumed three times daily after each meal for one month. One can also use capsules containing green tea extract ( such as Olimp Labs, Debica, Poland) taken daily with the morning meal for 3 months. (Reference: Top 10 Green Tea products, Labdoor, Retrieved on 1 January 2024)
• For low blood pressure suggested intake is 400 mL of green tea before lunch on a daily basis for at least 6 months.
• In the case of oral leukoplakia, 3 grams of mixed green tea or matcha powder is suggested to be taken by mouth and applied to the skin for a period of 6 months.
• For patients suffering from osteoporosis, doctors usually recommend capsules containing 500 mg of green tea polyphenols. These should be taken twice daily. (Reference: Green Tea: Health Benefits Uses and Side Effects, RX List, Retrieved 1 January 2024) 

Green Tea And Breastfeeding Side Effects – Can You Drink It, Healer Medicine, Google Images, licensed under CC BY 2.0

• For patients suffering from genital warts specific green tea extract ointment (Veregen, Bradley Pharmaceuticals; Polyphenon E ointment 15%, MediGene AG) are usually suggested. These should be applied three times daily for up to 4 months.
• In the case of oral leukoplakia, 3 grams of mixed green tea (or matcha tea) is suggested to be taken by mouth and applied to the skin for a period of 6 months.

Precautions and warnings of green tea for children and pregnant women:

• For children, Green tea is POSSIBLY SAFE if consumed in moderate amounts as part of daily food intake. Gargling three times daily for up to 90 days is also perfectly safe in children above 8 years old. (Reference: Green Tea: Health Benefits Uses and Side Effects, RX List, Retrieved 1 January 2024) 
• During pregnancy and Lactating mothers, green tea in small amounts of about 2 cups per day - is POSSIBLY SAFE. Two cups of green tea mean around 200 mg of caffeine which is fine. More than 2 cups of green tea might be linked to risks of miscarriage because of caffeine levels. Moreover, it has been found that such levels can lead to folic acid deficiencies. In lactating mothers, caffeine from the best green tea may pass into breast milk impacting the nursing newborn. (Reference: Flavonoids: The secret to health benefits of drinking black and green tea?, Harvard Health Publication, Retrieved 1 January 2024)

Detox Lemon Ginger Green Tea, Everyday Eileen, Google Images, licensed under CC BY 2.0

Who should avoid the best Green Tea?

• For patients suffering from anaemia (tired blood), irrespective of whether they are drinking the best green tea may make it worse. (Reference: The Safety of Green tea and green tea extract consumption in adults, Science Direct, Retrieved on 1 January 2024)
• For patients suffering from anxiety disorders, the caffeine in best green tea.
• Patients with bleeding disorders should avoid caffeine content in the best green tea.
• Green Tea during pregnancy should be avoided for more than 2 cups.
• Patients with a long history of heart condition should avoid green tea because of the caffeine content.
• Patients already suffering from type 2 diabetes should be careful while consuming green tea and should surely make it a point to monitor their blood sugar carefully.
• Green tea contains caffeine and should be avoided at times of diarrhoea.
• Drinking green tea increases pressure inside the eye and so patients suffering from Glaucoma should avoid. (Reference: Green Tea: Health Benefits Uses and Side Effects, RX List, Retrieved 1 January 2024) 
• Drinking green tea increases the amount of calcium in case of patients suffering from weak bones (cases of osteoporosis), however, one should be careful to limit their consumption of caffeine to 300 mg per day (approximately 2-3 cups of green tea). usually the best green tea quality contains higher nutrient value compared to the average priced green tea.
• The caffeine in best green tea, especially when taken in large amounts, can worsen diarrhoea and might worsen symptoms of Irritable bowel syndrome (IBS).
• Green tea extracts might make liver disease worse.
• The caffeine in best green tea might increase blood pressure in people with high blood pressure. 

Side Effects of drinking excess Green Tea, Life Berrys, Google Images, licensed under CC BY 2.0

Teacurry.com hopes that you thoroughly enjoyed the above research we have tried to put together in terms of Green tea. In case of questions or suggestions please let us know in comments below or write to us at tea@teacurry.com and we would be more than happy to assist you.