As ancient as Chinese silk, tea is one of the most widely consumed beverages in the world, next to water. Modern science confirms green tea polyphenols have a myriad of positive effects in cardiovascular health, overall health, and as a support for a healthy weight and oral health.

But what is green tea and why are there different colors of tea beverages? The millenary tea plant Camellia sinensis is a member of the Theaceae, a family of shrubs and trees, including the exotic camellias. The tea plant has been used as a beverage since 2,700 BC and many legends exist about its origin in China or possibly in India.

Tea is widely used in traditional medicine systems of China, Hong Kong, Japan, and Korea (1). All tea beverages, green, black, oolong and white tea, come from the same plant, but each undergoes different processing. Green tea derives from young shoots and buds, plucked from the plant, that are heated to inactivate enzymes that cause a dark color (4, 7). The heated leaves are rolled and dried using hot air. This millenary processing of the leaves yields the right amounts of versatile antioxidant polyphenols and caffeine (2, 3, 7).

Phytochemicals in Green Tea

The average amount of green tea consumed in Asian countries is equivalent to three cups per day (2, 3). A cup of green tea usually has 80-106 milligrams per cup of polyphenols (2, 3). The most important polyphenols in green tea are the flavonoids, with catechins making up to 80–90 percent of the flavonoids, and, approximately 40 percent of the water-soluble solids in green tea. Black tea has far fewer active catechins than green tea (7).

Positive Health Benefits

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 (1).

Over the past 15–20 years, additional clinical research studies have been conducted to specifically evaluate the benefits of consuming green tea and its extracts (8). Contemporary research confirms green tea catechins have a variety of benefits in digestive health, cardiovascular health, supporting weight loss, cellular health, bone and blood health, support for kidney function, healthy urination, and oral health (7). Their beneficial use in sports is also being investigated.

Safety of Green Tea

Traditional green tea infusions made with young leaves and leaf buds, are often consumed daily in Asian cultures, as a safe practice since they’re consumed in moderate amounts (3, 5, 6, 8). No side effects have been found in clinical trials (3, 8). Experts agree that green tea consumed at the traditional amount of three cups a day is considered safe (European Food Safety Authority) (2, 8).

The Isagenix no-compromise quality standards include the use of carefully sourced raw materials undergoing stringent analytical testing procedures to detect the presence of contaminants such as pesticides, heavy metals, microbes, etc. Isagenix green tea extracts are also made using a hot water extraction process, which replicates the traditional hot water brew preparation of teas, used for centuries around the world.

References

  1. 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.
  2. 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.
  3. Gruenwald J, Brendler T, and Jaenicke C. PDR for Herbal Medicines. Medical Economics Company, Inc. 2000. Montvale, NY.
  4. Barrett, M. The handbook of clinically tested herbal remedies, Vol. 2. 2004. Haworth Herbal Press: New York.
  5. Imai K and Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. British Medical J. 1995; 310, 693–696.
  6. Nemecz G. Green tea. US Pharmacist. 2000;67-70.
  7. Reygaert WC. An Update on the Health Benefits of Green Tea, Beverages. 2017;3, 6. doi:10.3390/beverages3010006.
  8. EFSA, 2006. European food safety authority scientific committee on food and scientific panel on dietetic products, nutrition and allergies. Tolerable Upper Intake Levels for Vitamins and Minerals. Available at: http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf.