Tea comes from the plant Camellia sinensis, and is consumed around the world as green, black or oolong tea (1). Tea is widely used in traditional medicine systems of China, Hong Kong, Japan and Korea (2).
Green tea is the second most popular beverage in the world (3), and it’s estimated that about 2.5 million tons of tea leaves are produced each year. Around 20% of this is produced as green tea. Green tea is mainly consumed in Asia, some parts of North Africa, the United States and across Europe (4).
What’s the difference between green tea and black tea?
For many centuries it was believed that black tea and green tea came from different plants. However, it is now understood they come from the same species, the difference being black tea is fermented (1). The most significant effects on human health have been observed with the consumption of green tea (4).
Green tea and black tea are from the same plant, however are processed differently. To produce green tea, freshly harvested leaves are immediately steamed to prevent fermentation, yielding a dry stable product. This steaming process destroys the enzymes responsible for breaking down the colour pigments in the leaves and allows the tea to maintain its colour during processing (4).
Health benefits of green tea
The average amount of green tea consumed in Asian countries is equivalent to three cups per day (5, 6). Green tea is a rich source of polyphenols, and many of the commonly believed health benefits of green tea are attributed to the high polyphenol content of this beverage, particularly catechins. Many of these benefits, including antioxidative, were attributed to its most abundant catechin, epicatechin gallate (EGCG) (3, 4).
From 1985 to 2000, more than 29 clinical studies on tea demonstrated its positive effects in cardiovascular health, digestive health, overall health, and in supporting weight management. Most of the studies were large population epidemiological studies on the influence of black and/or green tea consumption on health (2).
Additional clinical research studies have recently been conducted to specifically evaluate the benefits of consuming green tea and its extracts (7). Contemporary research confirms green tea catechins have a variety of benefits including in digestive health, cardiovascular health, supporting weight loss (8).
Green tea in e-Shot
Isagenix designed e-Shot to include caffeine from only natural sources including green tea, along with yerba mate. With 80mg of plant-based caffeine per e-Shot, it’s equivalent to the amount of a cup of coffee and for a boost at any time of day.
- Kew Gardens. Camellia sinensis. Available at: http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:828548-1 (accessed 9th February 2018)
- Blumenthal M, Hall T, Goldberg A, Kunz T, Dinda K, Brinckmann J, et al. The ABC Clinical Guide to Herbs. Austin, TX: American Botanical Council; 2003.
- Huang J, Wang Y, Xie Z, Zhou Y, Zhang Y, Wan X. The anti-obesity effects of green tea in human intervention and basic molecular studies. Eur J Clin Nutr 2014;68:1075-87
- Chacko S, Thambi P, Kuttan R, Nishigaki I. Beneficial effects of green tea: A literature review. Chin Med J 2010;5:13
- Dekant W, Fujiib K, Shibatac E, Moritab O, Shimotoyodom A. Safety assessment of green tea based beverages and dried green tea extracts as nutritional supplements. Toxicology Letters. 2017;277, 104-108.
- Gruenwald J, Brendler T, and Jaenicke C. PDR for Herbal Medicines. Medical Economics Company, Inc. 2000. Montvale, NY.
- European Food Safety Authority. Tolerable Upper Intake Levels for Vitamins and Minerals. Available at: http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf (accessed 9th February 2018).
- Reygaert WC. An Update on the Health Benefits of Green Tea, Beverages. 2017;3, 6.