Green Tea
OTHER NAME: Camellia sinensis
Description
A brewed green tea is typically green, yellow or light brown in color, and its flavor profile can range from grass-like and toasted (pan fired) to vegetal, sweet and seaweed-like (steamed). If brewed correctly, most green tea should be quite light in color and only mildly astringent.
Camellia sinensis plant produces green, black, and oolong teas, however they are processed differently. For green tea, the plant leaves are steamed, pan fried, and dried.
Uses
Tea has been used for medicinal purposes in China and Japan for thousands of years.
Green tea as a beverage or dietary supplement is promoted for improving mental alertness, relieving digestive symptoms and headaches, and promoting weight loss. Green tea and its components, including epigallocatechin-3-gallate (EGCG), have been studied for their possible protective effects against heart disease and cancer.
Green tea contains powerful antioxidants called polyphenols which have been studies as cancer chemopreventative agents. According to a study published in The American Journal of Clinical Nutrition, green tea supplements produced the highest levels of polyphenols compared to black and green tea. Therefore, ingesting green tea supplements may be more effective in supplying the body with antioxidants than sipping green tea.
Although many studies have been done on green tea and its extracts, there are yet to be any definite conclusions on whether green tea has beneficial effects for most of its purposes.
The U.S. Food and Drug Administration (FDA) has approved a topical ointment, sinecatechins (brand name Veregen), which includes extracted components of green tea leaves and is used for the treatment of genital warts.
Side Effects
Green tea, when consumed as a beverage, is believed to be safe when used in amounts up to 8 cups per day. Keep in mind that the amount of caffeine stated on the label is the added caffeine and not the caffeine that naturally occurs in green tea.
Drinking green tea may be safe during pregnancy and while breastfeeding when consumed in amounts up to 6 cups per day (no more than about 300 mg of caffeine).
Although uncommon, liver problems have been reported in a number of people who took green tea products, primarily green tea extracts in pill form. People with liver disease should consult a health care provider before taking products with green tea extract. People taking green tea extracts, especially those with liver disease, should discontinue use and consult a health care provider if they develop symptoms of liver trouble (such as abdominal pain, dark urine, or jaundice).
Green tea may interact with other medicines. Green tea at high doses has been shown to reduce blood levels and therefore the effectiveness of the drug nadolol, a beta-blocker used for high blood pressure and heart problems.
Sources
Green tea [Internet]. National Center for Complementary and Integrative Health. [cited 2022 Jul 20];Available from: https://www.nccih.nih.gov/health/green-tea
What is Green Tea? [Internet]. Teatulia. [cited 2022 Jul 20];Available from: https://www.teatulia.com/tea-101/what-is-green-tea.htm
Davis JL. Green tea capsules loaded with antioxidants [Internet]. WebMD. 2004 [cited 2022 Jul 20];Available from: https://www.webmd.com/food-recipes/news/20041215/green-tea-capsules-loaded-with-antioxidants
Additional Sources:
Botten D, Fugallo G, Fraternali F, et al. Structural properties of green tea. The Journal of Physical Chemistry B 2015;119 (40), 12860-12867. doi: 10.1021/acs.jpcb.5b08737
Kochman J, Jakubczyk K, Antoniewicz J, Mruk H, Janda K. Health benefits and chemical composition of matcha green tea: A review. Molecules 2020;26(1):85. doi: 10.3390/molecules26010085. PMID: 33375458; PMCID: PMC7796401.
Musial C, Kuban-Jankowska A, Gorska-Ponikowska M. Beneficial properties of green tea catechins. International Journal of Molecular Sciences 2020;21(5):1744. doi: 10.3390/ijms21051744. PMID: 32143309; PMCID: PMC7084675.