Green tea (GT) heals everything, says a health freak at the gym. There's nothing a green tea can't help with, he exclaims. Will there be any side effects of green tea, asked a lady, for which he exclaimed, GT is the best with zero effects. His words made them believe so. Is it really the fact?
GT has been the most overrated health drink for a decade. It was believed that GT has all pros with no or minimal cons. Let's explore the facts of green tea in the following paragraphs.
Tea is the second most common drink consumed all over the world, with water occupying the first place. Tea is available in 3 forms- Green tea, oolong tea and black tea.
Statistics state that Great Britain is the largest consumer of tea in the world, approximately 540ml per day. On global count, the average consumption of tea is about 120ml per person.¹
The most commonly used tree species for tea is Camellia sinensis, most commonly cultivated in Kenya, China and India. GT differs from black tea based on processing procedure.
Tea consists of caffeine, carbohydrates, polyphenols and minerals. GT mainly consists of catechins and black tea consists of tannins. Green tea is a rich source of catechins after chocolate, red grapes, wine and apples. European Food Safety Security stated that 126 mg of catechins can be present in 100 ml of green tea.¹
Studies state that GT has many health benefits such as antiaging, reducing body mass, increasing heart health and improving the health of nerves.¹
Drinking green tea in the morning
Nutrients we can get from green tea
As said earlier, GT is rich supply of catechins, which are a class of flavanols which can be enlisted as
- Epigallocatechin-3-gallate (EGCG)
- Epicatechin-3-gallate (ECG),
- Epigallocatechin (EGC)
- Epicatechin (EC)
The other components of GT include phenolic acids, polyphenols(catechins), theanine, proanthocyanidins, amino acids, proteins and fats.
It is said that a typical cup of 250-350mg of GT consists of 30-42% catechins and 3-6% caffeine.³
Benefits of drinking green tea in the morning
GT, because of its chemical composition, can contribute to one's health in many ways-
- Antioxidative stress- Human body contains free ions like oxygen and nitrogen that cause damage to various vital organs. Catechins help in neutralising these free radicals
- Antiphotoaging- Photoaging is a process of damage of skin due to exposure to UV radiation and age factors. Green tea can promote collagen growth in skin, fighting against photoaging making one look much younger than their age
- Arthritis- Chance of getting arthritis decreases with green tea consumption. Increase in bone density has also been discovered among those who consume green tea on a daily basis
- Diabetes- Green tea can help in insulin secretion and glucose metabolism, helping to keep blood glucose level at a minimum
- Obesity- Consumption of green tea results in reduction of visceral fat and lipid metabolism, thereby helping in reducing weight
- Neurological disorders-The component theanine, found to be helping in synthesis of nerves, increases transmitters that help in repair of nerves and improves health of nerves
- Hepatoprotective- Galactomine induces liver injury similar to hepatitis. Green tea counteracts the action of galactamine, thus improving the health of the liver
- Autoimmune conditions- Epigallocatechin-3-gallate has been found to help in treating induced autoimmune conditions in mice, byreducing inflammation and damage
- Cholesterol maintenance- Catechins helps in reducing the very low density lipids and low density lipids ( VLDL and LDL), which results in heart diseases
- Cardiovascular health- Green tea is said to be contributing to reducing harmful lipids causing the damage of arteries (atherosclerosis)
- Cancer- Due to antioxidant properties of catechins and theaflavins, there can be reduced free radical activity that can contribute to reduced incidence of cancer. Apoptosis is a process of killing one's own damaged cells. Green tea helps in apoptosis, thus killing abnormal cancer cells. Catechins in green tea are found to produce hydrogen peroxide (H₂O₂), preventingthe attachment of cancer cells in distant sites thus promoting antimetastatic property¹ ² ³ ⁴
The various types of cancer that are proved to have less occurrence with green tea consumption are as follows-
- Skin cancer
- Prostate cancer
- Breast cancer
- Lung cancer
- Pancreatic cancer
- Stomach cancer
- Bladder cancer¹ ² ³ ⁴
EGCG also said to have properties of
- Anti Inflammatory
- Antidental caries¹ ² ³ ⁴
Research says catechins (Epigallocatechin-3-gallate) plays a major role in most of the health benefits of GT. Thebioavailability of the EGCG seems to be affected by food. EGCG seem to be absorbed lesser when consumed with food. Therefore its the best to take green tea on empty stomach, i.e in morning time.⁵
Side effects of drinking green tea in the morning
Green tea is beneficial and harmful too. GT when taken in higher amounts and concentrations has been proven to cause liver damage.
Mark Brumenthal, executive director of American Botanical Council, stated that high concentration of EGCG on fasting state might affectthe liver. They might have different effects when the liver is metabolising the food.
Signs of liver damage include jaundice and dark urine.
Increased oxidative stress is noticed when higher concentrations of GT are consumed, and is proven to cause DNA damage with chromosomal damage.⁶
Studies state that the adverse effects of GTinclude:-
Minimal gastric irritation and gastric tract damage at concentration of 2000 mg/kg/day. They present with the symptoms of diarrhoea and vomiting. Gastric damage occurs due to gastric erosion, gastric tract dilatation, ulcerations and blood loss from the gut.
Consumption of higher concentration of catechins has been found to cause damage of vital organs like-
- Liver damage
- Kidney damage
- Thymus damage
- Spleen damage
- Pancreas damage⁶
When is it too much?
The general consumption of GT is about 4 cups daily. It may reach up to 10 cups in some of the countries. When consuming more concentrated green tea, it causes health issues.
The safe level for the intake of catechins or pure form of EGCG is about 338mg/ day in bolus form. The safe level of intake of 704 mg/day is better in beverage form. The gut can be affected when the consumption of EGCG reaches up to 67.8-105 mg/kg/ day.
Studies state that consumption of 500-1000 mg/kg/ day can also affect reproductive organs.⁶
Dosage of 2334 mg /kg/ day results in thyroid malfunctions.⁶ ⁷
Anything more than necessary is poison. Though the consumption of green tea is beneficial in many ways, it does have some cons when consumed at higher concentrations. Studies giving mixed results on the best time to consume GT. More research has to be planned in this direction. Meanwhile, consumption of green tea should be justified and limited to avail the pros and avoid the cons.
GT- Green tea
- Prasanth MI, Sivamaruthi BS, Chaiyasut C, Tencomnao T. A Review of the Role of Green Tea (Camellia sinensis) in Antiphotoaging, Stress Resistance, Neuroprotection, and Autophagy. Nutrients 2019;11:474. https://doi.org/10.3390/nu11020474.
- Musial C, Kuban-Jankowska A, Gorska-Ponikowska M. Beneficial Properties of Green Tea Catechins. Int J Mol Sci 2020;21:1744. https://doi.org/10.3390/ijms21051744.
- Khan N, Mukhtar H. Tea and Health: Studies in Humans. Curr Pharm Des 2013;19:6141–7.
- SUZUKI Y, MIYOSHI N, ISEMURA M. Health-promoting effects of green tea. Proc Jpn Acad Ser B Phys Biol Sci 2012;88:88–101. https://doi.org/10.2183/pjab.88.88.
- Naumovski N, Blades BL, Roach PD. Food Inhibits the Oral Bioavailability of the Major Green Tea Antioxidant Epigallocatechin Gallate in Humans. Antioxidants (Basel) 2015;4:373–93. https://doi.org/10.3390/antiox4020373.
- Hu J, Webster D, Cao J, Shao A. The safety of green tea and green tea extract consumption in adults – Results of a systematic review. Regulatory Toxicology and Pharmacology 2018;95:412–33. https://doi.org/10.1016/j.yrtph.2018.03.019.
- García-Cortés M, Robles-Díaz M, Ortega-Alonso A, Medina-Caliz I, Andrade RJ. Hepatotoxicity by Dietary Supplements: A Tabular Listing and Clinical Characteristics. Int J Mol Sci 2016;17:537. https://doi.org/10.3390/ijms17040537.