EGCG & other polyphenols in green & black tea!

Tea is the richest beverage in polyphenols. Both green and black tea are high in EGCG which has potent antioxidant properties. A cup of tea provides up to 600 mg of polyphenols, of which 200 mg are EGCG.

Health benefits of tea due to its high polyphenol content

Green tea has many health benefits due to its high polyphenol content. In fact, tea is one of the richest foods in polyphenols.

Polyphenols in tea may reduce the risk of various degenerative diseases, such as cardiovascular diseases and cancer. Additionally, green tea may be beneficial in reducing the plasma concentration of cholesterol (1).

In fact, the regular consumption of tea may prolong life. According to a study, the average life span was 66 years for men who had more than 3 cups of green tea per day and 68 years for women. But, the average life span was 70 years for men who had more than 10 cups of green tea per day. It was 74 years for women (23).

Green tea significantly increases the antioxidative status of the body (1,15).

What polyphenols are in tea?

More than 1,000 research articles can be found in the current literature, with an emphasis on green tea as an antioxidant. The main ingredient for the antioxidant properties of green tea is believed to be a type of polyphenol, named EGCG. EGCG has powerful antioxidant properties (1,11).

Actually, the tea polyphenols are of the flavonoid group, named catechins. Catechins are about 30% of the dry leaf weight from the tea plant. Catechins can be analyzed further to EGCG, EGC, and EC. Tea leaves are particularly rich in EGCG.

Tea is the most popular beverage in the world, second only to water. Its high consumption can help us boost our daily polyphenol intake. A study measured that the consumption of cocoa, tea or coffee could increase the daily polyphenol intake by 500–1,000 mg (17).

Green or black tea is richer in EGCG & other polyphenols?

Green tea, black tea, and oolong tea are all derived from the Camellia sinensis plant. Only the fermentation process is different among these types of tea.

Green tea isn’t fermented. On the contrary, black tea is completely fermented. Oolong tea contains a mixture of both fermented and non-fermented leaves.

In the production of black tea, the tea leaves are crushed. About 75% of catechins contained in the tea leaves undergo enzymatic transformation and partial polymerization. The polyphenol composition of black tea depends on the processing method.

Black tea contains approximately (2):

  • catechins (10–12%),
  • theaflavins (3–6%),
  • thearubigins (12–18%),
  • flavonols (6–8%),
  • phenolic acids (10–12%)

In fact, all types of tea are rich in EGCG and other polyphenols.

In general, green tea has a higher total phenol content as compared to black tea. A gram of green tea has between 140 and 210 mg of polyphenols, whereas a gram of black tea has only 80-170 mg of polyphenols. Hence, green tea has about 24% more polyphenols than black tea.

Actually, the mean daily intake of EGCG from green tea consumption ranges from 90 to 300 mg per day. Heavily tea consumers may get up to 866 mg of EGCG per day (25).

1 gram of green tea solids contains about (14):

  • 73 mg of EGCG
  • 68 mg of EGC
  • 22 mg of ECG
  • 25 mg of EC

In order to prepare a cup of green tea, we use about 1.8 to 3 g of green tea solids. This means that we consume about 200 mg of EGCG per cup of tea.

Sources:

  1. NCBI– PMC: Tea polyphenols, their biological effects and potential molecular targets
  2. NCBI– PMC: Tea polyphenols for health promotion
  3. NCBI– PMC: Recent advances on tea polyphenols
  4. NCBI- Pubmed.gov: Cancer chemoprevention with dietary phytochemicals.
  5. NCBI- Pubmed.gov: The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer.
  6. NCBI- Pubmed.gov: Cancer-preventive effects of drinking green tea among a Japanese population.
  7. NCBI- Pubmed.gov: Influence of drinking green tea on breast cancer malignancy among Japanese patients.
  8. NCBI- Pubmed.gov: The green tea polyphenol (-)-epigallocatechin gallate and green tea can protect human cellular DNA from ultraviolet and visible radiation-induced damage.
  9. NCBI- Pubmed.gov: Effect of increased tea consumption on oxidative DNA damage among smokers: a randomized controlled study.
  10. NCBI- Pubmed.gov: Oxidative stress profiling: part I. Its potential importance in the optimization of human health.
  11. Prevention of reactive oxygen species-induced oxidative stress in human microvascular endothelial cells by green tea polyphenol.
  12. The effect of green tea on oxidative stress.
  13. NCBI- Pubmed.gov: In vivo antioxidant effect of green tea.
  14. Blood and urine levels of tea catechins after ingestion of different amounts of green tea by human volunteers.
  15. Effectiveness of moderate green tea consumption on antioxidative status and plasma lipid profile in humans.
  16. Risk of melanoma and vitamin A, coffee and alcohol: a case-control study from Italy.
  17. British Journal of Nutrition: Dietary reference intake (DRI) value for dietary polyphenols: are we heading in the right direction?
  18. Thermogenesis: Thermogenesis is defined as the dissipation of energy through the production of heat and occurs in specialized tissues including brown adipose tissue and skeletal muscle.
  19. Effect of a thermogenic beverage on 24-hour energy metabolism in humans.
  20. Mechanisms of hypolipidemic and anti-obesity effects of tea and tea polyphenols.
  21. Green tea and thermogenesis: interactions between catechin-polyphenols, caffeine and sympathetic activity.
  22. NCBI- Pubmed.gov: Can teatime increase one’s lifetime?
  23. Japanese green tea as a cancer preventive in humans.
  24. Critical Reviews in Food Science and Nutrition: Antioxidants in tea.
  25. European Food Safety Authority: Scientific opinion on the safety of green tea catechins.