Tea – the best source of polyphenols
Poles love tea – about 76-90 percent of the population consumes it on a daily basis, and most people drink 2-3 cups a day [1]. Already in traditional medicine it was considered a therapeutic agent, and contemporary research confirms its beneficial effects on the cardiovascular system, losing weight, and reducing the risk of cancer, among other things.
Polyphenols – natural chemical compounds that help fight free radicals in the body, and therefore have antioxidant effects – are considered the greatest source of health from tea. Polyphenols also exhibit anti-inflammatory and anticancer effects, support the entire cardiovascular system, have a beneficial effect on the composition of the intestinal microflora, and lower bad cholesterol (LDL) [2].
In addition to polyphenols, of course, tea contains caffeine, which stimulates the nervous system and heart function. Dry tea leaves have certain amounts of minerals, such as fluorine, manganese, chromium, selenium, calcium, magnesium and zinc. Their content depends on growing conditions, fermentation, and even the size of the leaves themselves. As one study reads:
“100 ml of tea provides 0.07 mg of zinc, 2 mg of magnesium and 5 mg of calcium, which means that a glass of tea covers in adults only 1-1.5% of the recommended daily intake of these components” [3].
However, the brew is a good source of manganese, a chemical element that is an antioxidant and, as a component of enzymes, helps in metabolic changes such as nutrient synthesis, digestion and energy production.
6 types of tea and their health benefits
Green tea
It is to it that we will devote the most space, because it is the healthiest, but also the best researched type of tea. Among others, it contains polyphenolic compounds from the flavanol group, flavonoids and phenolic acids – all of which exhibit antioxidant activity and have the potential to counteract arthritis and osteoarthritis. However, the main component of green tea are catechins, which have a positive impact on the cardiovascular system and prevent atherosclerosis.
There is a lot of talk that green tea can have anti-cancer effects. According to scientific studies, in Asia, where consumption of green tea is high, the incidence of cancer (prostate, breast, esophageal, lung, stomach, pancreatic and colon cancer) is lower compared to the West. Researchers believe that the catechins present in green tea actually have the potential not only to act as prevention against cancer, but also to support the body in the course of the disease [5].
In addition, green tea also has antiviral, antibacterial and anti-aging effects. It may lower blood pressure, thereby reducing the risk of stroke and ischemic heart disease [6].
All of these properties are of great importance for athletes, because they allow them to stay fit, recover faster after training and take care of their health, as well as... fight excess weight more efficiently. This happens by increasing postprandial thermogenesis (increasing metabolic rate) and fat oxidation [7].
Black tea
Good news for fans of black tea – it too has many health benefits, and is also rich in polyphenols. According to scientific studies [8], regular drinking of black tea helps reduce the risk of cardiovascular disorders and reduces bad cholesterol. Black tea leaves will have a positive impact on the fight against excess weight, because the polyphenols present in black tea improve digestion and absorption of lipids and complex sugar.
Black tea has the potential to lower high blood pressure, which carries the risk of complications such as heart failure, heart attack, stroke, kidney damage and atherosclerosis. The brew is also valuable for diabetics, as it lowers blood glucose levels, but also improves insulin levels.
Red tea, or rooibos
It is created by fermenting the leaves – this is where its slightly rusty color comes from. It contains no caffeine, but is rich in antioxidants. It positively affects blood pressure. In one study involving forty overweight adults at high risk of heart disease, drinking six cups of red tea a day for six weeks lowered LDL (bad) cholesterol while increasing HDL cholesterol levels [9]. So it will favor those who are overweight and want to lose weight.
White tea
It is quite expensive to grow, as it is produced entirely from leaf buds, which are covered with fluffy and white hair. They are harvested even before they have had a chance to develop. Compared to other types of tea, it has the most polyphenols and the least caffeine. Studies have shown that it works against inflammation, ischemia, atherosclerosis, type 2 diabetes, cancer and cardiovascular diseases.
Yellow tea
It is made from lightly fermented leaves. It is produced exclusively in China. The taste is mild and sweet. As in all types of tea, here you will also find a wealth of polyphenols, which will have a positive impact on heart function, and also likely to have an anti-cancer effect. Interestingly, yellow tea is recommended for people with gastrointestinal problems, as in studies it had a protective effect on the stomach, preventing injury and irritation [11].
Yerba Mate
If you’re looking for a coffee substitute, Yerba Mate (or Ilex paraguariensis) is a caffeine-rich product! And not only that – it also contains vitamin C, B1, B2 and B6, as well as small amounts of vitamin A and E. Yerba Mate, like all the brews described above, is rich in polyphenols. Scientists have found many reasons for drinking it:
Yerba Mate, as a powerful antioxidant, lowers cholesterol, (...) lowers blood and tissue lipid levels, so it can be used to counter obesity, hypertension and diabetes. It also has anti-inflammatory and antimicrobial effects, and even prevents some types of cancer [15].
Which tea will be best for physically active people?
Looking at the benefits of drinking different types of tea, it’s best to have them all on hand and enjoy them alternately. However, scientific research has focused most strongly on the beneficial effects of green tea – including for athletes.
It can be viewed as an ergogenic supplement (i.e. a substance that naturally supports exercise) that reduces fatigue and improves performance and endurance [12]. In turn, the catechins discussed above significantly increase energy in humans – exercise can become longer and more intense as a result. Green tea also has the potential to speed up post-workout recovery, reduce fatigue and muscle damage, and minimize the risk of injury [13]. The already mentioned polyphenols also reduce oxidative stress, which is dangerous for athletes.
Theine – is it an ingredient dangerous to health?
The theine found in tea is a compound that is identical in composition to caffeine – but is milder in effect. So it stimulates and reduces fatigue and feeling of drowsiness. It is said that it can be dangerous to health, but scientific sources do not confirm it:
Tea brewing results in weaker concentration of caffeine than coffee brewing. In addition, theine, reacting with tannin, forms tannin caffeate, which has a slower and gentler effect on the cardiovascular system and central nervous system than caffeine. Furthermore, theine does not accumulate in the human body, making poisoning with this compound almost impossible [14].
So you don’t have to worry about consuming any of the teas. However, if you have any doubts, and your doctor has forbidden you to consume caffeine and its derivatives – consult a specialist.
Is drinking tea with lemon dangerous to your health?
Finally, it is worth dispelling one more myth. Is it true that when lemon is added to tea, it produces aluminum citrate, which is harmful to health? Paweł Struciński, PhD, of the Department of Toxicology and Health Risk Assessment of The National Institute of Public Health – National Institute of Hygiene reassures: the health risk of combining these two ingredients does not pose any risk to health, although yes, trace amounts of aluminum citrate are then formed [16].
Cold brew from green tea not only for athletes
The properties of green tea are impressive. However, in order for green tea to be effective, you need to drink it regularly and daily, a minimum of two cups. On warmer days, it is worth making it into a so-called “cold brew”. Just pour water over the leaves at room temperature (in a glass dish), and then put them in the refrigerator for about ten hours. For example, you can add your favorite fruits to it. After this time the drink is ready – refreshing and great thirst quencher!
Also read an article about kombucha, which is made from tea and great for more than just summer. You will find it HERE.
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References:
[1] [2] [3] Regina Wierzejska, WPŁYW PICIA HERBATY NA ZDROWIE - AKTUALNY STAN WIEDZY, Zakład Żywienia i Dietetyki z Kliniką Chorób Metabolicznych i Gastroenterologii, PRZEGL EPIDEMIOL 2014; 68: 595 - 599.
[4] Niektóre aspekty leczniczego działania zielonej herbaty, Katedra Morfologii Funkcjonalnej Uniwersytetu Warmińsko-Mazurskiego w Olsztynie.
[5] Musial, C.; Kuban-Jankowska, A.; Gorska-Ponikowska, M. Beneficial Properties of Green Tea Catechins. Int. J. Mol. Sci. 2020, 21, 1744. https://doi.org/10.3390/ijms21051744.
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[8] Rasheed Z. Molecular evidences of health benefits of drinking black tea. Int J Health Sci (Qassim). 2019 May-Jun;13(3):1-3. PMID: 31123432; PMCID: PMC6512146.
[9] Marnewick JL, Rautenbach F, Venter I, Neethling H, Blackhurst DM, Wolmarans P, Macharia M. Effects of rooibos (Aspalathus linearis) on oxidative stress and biochemical parameters in adults at risk for cardiovascular disease. J Ethnopharmacol. 2011 Jan 7;133(1):46-52. doi: 10.1016/j.jep.2010.08.061. Epub 2010 Sep 15. PMID: 20833235.
[10] Irene Dini, in Functional and Medicinal Beverages, 2019, https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/white-tea, dostęp online: 06.07.2023.
[11] Wang Q, Zhao X, Qian Y and Wang R: In vitro antioxidative activity of yellow tea and its in vivo preventive effect on gastric injury. Exp Ther Med 6: 423-426, 2013.
[12] Murase, T.; Haramizu, S.; Shimotoyodome, A.; Nagasawa, A.; Tokimitsu, I. Green tea extract improves endurance capacity and increases muscle lipid oxidation in mice. Am. J. Physiol.-Regul. Integr. Comp. Physiol. 2005, 288, R708–R715.
[13] Özyurt, H.; Luna, C.; Estévez, M. Redox chemistry of the molecular interactions between tea catechins and human serum proteins under simulated hyperglycemic conditions. Food Funct. 2016, 7, 1390–1400.
[14] Monika Michalak-Majewska, Właściwości herbaty. Część 1. Znaczenie żywieniowe, Nauka. Przyroda. Technologie, 2011, Tom 5, Zeszyt 6.
[15] Gawron-Gzella A, Chanaj-Kaczmarek J, Cielecka-Piontek J. Yerba Mate-A Long but Current History. Nutrients. 2021 Oct 21;13(11):3706. doi: 10.3390/nu13113706. PMID: 34835962; PMCID: PMC8622869.
[16] Herbata z cytryną - szkodzi czy nie?, https://zdrowie.pap.pl/dieta/herbata-z-cytryna-nie-szkodzi, dostęp online: 14.07.2023.