Tea is the most popular beverage in the world after water. Its preparation is simple: pouring hot water over cured leaves of the Camellia sinensis plant. It can be served hot or cold, anytime, anywhere, for any occasion. The flavor and color of tea vary by where the tea leaves are harvested and how they are processed.
While teas do not contain significant nutrients, they are rich in polyphenols. Tea polyphenols are bioactive compounds that give tea distinct flavor and aroma and may have health-promoting benefits.
Examples of polyphenols in tea:
- Flavonols
- Theaflavins
- Catechin
Tea polyphenols act as antioxidants, which help to neutralize the damaging effect of free radicals in the body. Free radicals, over time, can damage elements in the body, such as DNA and lipid profiles.
Benefits of Tea Polyphenols
HEART AND BRAIN HEALTH
Some studies found that people who regularly consume one or more cups of tea daily have a lower risk of cardiovascular disease. In a study of green and oolong tea consumption, regular consumption for one year reduced the risk of developing hypertension (1). Polyphenol, EGCG, in tea was also found to increase the levels of antioxidants in the body and exhibit a protective effect on brain cells and functions (2-3).
SKIN HEALTH
Tea consumption has also been linked to improving skin health. Recent research showed that topical application and dietary supplementation of green or white tea extracts may protect the skin from UV damage by increasing DNA repair (4-5).
WEIGHT MANAGEMENT
Several studies suggest that drinking plain tea may help with weight management. Tea flavonoids help increase metabolic rate, increase fat oxidation and improve insulin activity (6-8). Catechins, rich in green tea, can also provide a shift in metabolism that may improve weight loss and maintenance (9-11).
Reference:
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Yang, Y.C., et al. “The Protective Effect of Habitual Tea Consumption on Hypertension.” ACC Current Journal Review, vol. 13, no. 10, 2004, p. 18., https://doi.org/10.1016/j.accreview.2004.08.107.
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Tomata, Yasutake, et al. “Green Tea Consumption and the Risk of Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study.” The American Journal of Geriatric Psychiatry, vol. 24, no. 10, 2016, pp. 881–889., https://doi.org/10.1016/j.jagp.2016.07.009.
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Cheng-Chung Wei, James, et al. “Epigallocatechin Gallate Attenuates Amyloid β-Induced Inflammation and Neurotoxicity in EOC 13.31 Microglia.” European Journal of Pharmacology, vol. 770, 2016, pp. 16–24., https://doi.org/10.1016/j.ejphar.2015.11.048.
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Sharma, Pooja, et al. “Tea Polyphenols for the Prevention of UVB-Induced Skin Cancer.” Photodermatology, Photoimmunology & Photomedicine, vol. 34, no. 1, 2017, pp. 50–59., https://doi.org/10.1111/phpp.12356.
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Hakim, Iman A, and Robin B Harris. “Joint Effects of Citrus Peel Use and Black Tea Intake on the Risk of Squamous Cell Carcinoma of the Skin.” BMC Dermatology, vol. 1, no. 1, 2001, https://doi.org/10.1186/1471-5945-1-3.
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Vernarelli, Jacqueline A., and Joshua D. Lambert. “Tea Consumption Is Inversely Associated with Weight Status and Other Markers for Metabolic Syndrome in US Adults.” European Journal of Nutrition, vol. 52, no. 3, 2012, pp. 1039–1048., https://doi.org/10.1007/s00394-012-0410-9.
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Hursel, R, et al. “The Effects of Green Tea on Weight Loss and Weight Maintenance: A Meta-Analysis.” International Journal of Obesity, vol. 33, no. 9, 2009, pp. 956–961., https://doi.org/10.1038/ijo.2009.135.
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Venables, Michelle C, et al. “Green Tea Extract Ingestion, Fat Oxidation, and Glucose Tolerance in Healthy Humans.” The American Journal of Clinical Nutrition, vol. 87, no. 3, 2008, pp. 778–784., https://doi.org/10.1093/ajcn/87.3.778.
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Hursel, R., et al. “The Effects of Catechin Rich Teas and Caffeine on Energy Expenditure and Fat Oxidation: A Meta-Analysis.” Obesity Reviews, vol. 12, no. 7, 2011, https://doi.org/10.1111/j.1467-789x.2011.00862.x.
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Nagao, Tomonori, et al. “A Green Tea Extract High in Catechins Reduces Body Fat and Cardiovascular Risks in Humans*.” Obesity, vol. 15, no. 6, 2007, pp. 1473–1483., https://doi.org/10.1038/oby.2007.176.
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Hursel, Rick, and Margriet S Westerterp-Plantenga. “Catechin- and Caffeine-Rich Teas for Control of Body Weight in Humans.” The American Journal of Clinical Nutrition, vol. 98, no. 6, 2013, https://doi.org/10.3945/ajcn.113.058396.