Tea is one of the most widely consumed products around the world. In particular, black tea is the most popular type, with green tea taking second place, followed by oolong and white variations of this drink (Tea and cancer prevention, n.d.). People traditionally attribute health benefits to this ancient beverage, brewed from the dried leaves of Camellia sinensis. However, the properties of tea are diverse and often understudied. The effects of its consumption may range depending on varied factors and contexts. Therefore, the health benefits of tea require careful consideration and analysis.
First, it is necessary to observe that the health value of tea largely relies on its chemical structure and active components, namely, the content of polyphenols, which include catechins. To be more specific, catechins found in tea are probably responsible for their beneficial effects. In this context, green tea contains the highest concentrations of catechins. For instance, the level of the most active type of catechins, which is epigallocatechin-3-gallate (EGCG), is 117–442 mg/L in green tea infusion (Tea and cancer prevention, n.d.). Meanwhile, black tea and other types of this beverage contain much lower concentrations of catechins, but combinations of other complex polyphenols, such as thearubigins and theaflavins.
The abovementioned chemical properties of tea ensure its potent antioxidant activity, which is a key mechanism of its therapeutic effect. In other words, tea components are capable of scavenging free radicals, thus inhibiting the detrimental process of oxidation in the human body. Indeed, tea components can prevent DNA damage, protect against impairment with ultraviolet B radiation, and even act as immune response-modulating agents (Tea and cancer prevention, n.d.). Studies have shown that catechins and theaflavins inhibit several enzymes, including hydroxyl-3-methyl-glutaryl-CoA reductase, which is involved in cholesterol synthesis (Andrew et al., 2017). Therefore, researchers assume that “regular consumption of tea” can probably “improve glucose and lipid metabolism” (Andrew et al., 2017, p. 1178). At the same time, these findings come from in vitro studies, which means that the antioxidant potency of polyphenols is a laboratory-confirmed fact. However, clinical trials and reliable evidence are still necessary to prove the antioxidant effects of tea in the human body. Indeed, scientists admit serious difficulties in measuring the antioxidant properties of tea polyphenols primarily due to “rapid degradation and poor absorption of the original chemical species in vivo” (Andrew et al., 2017, p. 1178). As one can observe, the antioxidant effects of tea constitute a promising direction for research and require further evaluation and measurement.
Moreover, the majority of other health benefits of tea also remain understudied and unproven. Hence, scholars have not obtained sufficient evidence as to its beneficial effects on blood pressure, cholesterol level, and weight loss (Green tea, n.d.). Apart from the antioxidant activity, which may be highly favorable as such, other potential benefits of tea still require the focus of attention from scientists. The same is true for the use of tea in cancer treatment and prevention, which has recently been a subject of active debate. For example, in several studies, tea polyphenols suppressed “tumor cell proliferation and invasiveness” (Tea and cancer prevention, n.d., para. 8). However, the role and mechanisms of tea polyphenols in cancer prevention remain understudied and therefore require further research. In general, the National Cancer Institute refrains from recommending “for or against using green tea to reduce the risk of any type of cancer” (Green tea, n.d., para. 3). In other words, at present, the studies obtained only a limited amount of reliable and consistent data to reach any definite conclusions for this matter.
One must also keep in mind that the beneficial properties of tea strongly rely on the techniques of its preparation. For instance, ready-to-drink and iced beverages do not provide the same polyphenol concentration as the traditionally brewed tea does. The parameters of infusion, such as temperature, brewing time, and the amount of tea, also determine the ultimate health value of the drink. In other words, the therapeutic effects of tea constitute a complex and delicate phenomenon, which requires careful consideration of numerous factors if one intends to enjoy the full range of its health benefits.
At the same time, the consumption of this beverage may also have adverse effects. In fact, the potentially harmful consequences include “excess intestinal gas, nausea, heartburn, stomachache, abdominal pain, dizziness, headache, and muscle pain” (Tea and cancer prevention, n.d., para. 9). Besides, “catechin compounds are hepatotoxic,” therefore, people with liver damage must drink tea with caution (Bolton, 2019, para. 5). Furthermore, tea is a caffeinated drink and requires consumption in moderate amounts. In particular, black tea contains the highest concentrations of caffeine, followed by oolong, green, and white tea varieties. Consequently, excessive intake of caffeine is known to cause “tachycardia, palpitations, insomnia, restlessness, nervousness, tremors, headache, abdominal pain, nausea, vomiting, diarrhea, and diuresis” (Tea and cancer prevention, n.d., para. 9). As one can observe, tea consumption may not trigger adverse effects in healthy adults. Nevertheless, it can exacerbate the condition in people with health problems, especially those affecting the cardiovascular and gastrointestinal systems.
Moreover, tea also contains a certain amount of aluminum found in soils under specific natural circumstances. Consequently, this neurotoxic element may accumulate in the human body and lead to “osteomalacia and neurodegenerative disorders, especially in individuals with renal failure” (Tea and cancer prevention, n.d., para. 11). Besides, tea can suppress the absorption of iron from the diet. As a result, it can be harmful to people with iron-deficiency anemia. Therefore, the researchers recommend drinking tea between meals to minimize this adverse effect. Hence, tea consumption must not exceed the recommended amounts of intake and requires caution in people with known underlying diseases. As one can easily observe, specific conditions and context of tea consumption exert a significant influence on the effect of this beverage on the human body. In particular, if taken excessively or by people at risk, it can cause detrimental health outcomes.
In general, world tea production is steadily increasing every year. In fact, scientists expect that black tea exports will have reached 1.67 million tonnes by 2023 (Chang, 2015). Among primary commercial sources, China is the largest tea-producing country, whose output accounts for “more than 38 percent of the world total” (Chang, 2015, p. 3). India is the second-largest tea producer in the world. Kenya is the largest exporter of tea, “followed by Sri Lanka, India, Vietnam, Indonesia, Malawi, Uganda, and Tanzania” (Chang, 2015, p. 9). It is also necessary to observe that tea can be consumed not only as a beverage. For instance, green tea “is sold in liquid extracts, capsules, and tablets and is sometimes used in topical products” (Green tea, n.d., para. 1). Thus, tea production is a fast-paced and rapidly developing area of business and commerce.
One must also remember about potential nutraceutical-drug interactions of tea products. In other words, tea as a natural supplement can have unexpected adverse effects when interacting with medicinal substances. The studies have also demonstrated that green tea interferes with the action of certain medications. For example, it can reduce the effectiveness of nadolol, “which is a beta-blocker used for high blood pressure and heart problems” (Green tea, n.d., para. 4). Moreover, green tea can lead to “drug-induced liver injury” (Andrew et al., 2017, p. 1189). (Tsai et al., 2012). That is to say, the potential pharmacokinetic interaction between tea products and drugs may be highly detrimental to human health.
In general, the U.S. Food and Drug Administration (FDA) recognizes tea as a safe food item. Nevertheless, the regulatory status of tea involves specific issues, which can affect this status in the future. For instance, tea supplements in the form of pills and powders are currently becoming increasingly popular. However, it is difficult from the regulatory point of view to ensure their effectiveness and marketing transparency. Recently, there was a case with several dietary supplement companies suspected of illegal marketing of green tea products (Bolton, 2019). In particular, their products claimed, “to prevent or cure serious diseases, including Alzheimer’s, or provide substantial health benefits, especially in weight control” (Bolton, 2019, para. 1). As a result, they obtained an official warning from the FDA. It is evident that these regulation activities “will affect green tea products, both their production, safety, labeling, and marketing” (Bolton, 2019, para. 2). In such a manner, FDA officials aim to prevent illegal and fraudulent marketing of products with unproven and dubious health benefits.
It is necessary to point out that the regulatory problem with tea products stems from the features of their categorization. Indeed, supplements have the status of food items, and thus “fall outside the strict requirements of pharmaceutical testing and certification” (Bolton, 2019, para. 4). In other words, the FDA is unable to verify and validate the accuracy of ingredients, health benefits, and other vital characteristics. At the same time, specific groups of tea products have already obtained legal status. For example, the FDA approved green tea extract ointments “as a prescription drug for treating genital warts” (Green tea, n.d., para. 3). The implications of the abovementioned issues for the future development of the tea industry rely on the increased oversight of supplements aimed at the prevention of misbranding and ensuring consumer safety. As one can observe, the regulatory status of tea products remains uncertain and therefore requires further consideration and standardization.
Thus, tea is a potentially useful and beneficial product. The chemical properties of tea ensure its potent antioxidant activity, which can exert a favorable effect on the human body. However, this ancient beverage still requires elaborate studies and clinical trials to confirm its claimed health benefits and exclude the possibilities of adverse effects. As with any other medicinal substance or food item, tea consumption requires moderation and due account for a specific context, such as the preparation techniques or underlying diseases. Tea products also need the adjustment of their regulatory status primarily to protect consumers and avoid any marketing misconduct. Therefore, people can enjoy the beneficial properties and health value of tea only while observing the abovementioned conditions.
References
Andrew, R., & Izzo, A. A. (2017). Principles of pharmacological research of nutraceuticals. British Journal of Pharmacology, 174(11), 1177–1194.
Bolton, D. (2019). FDA warns dietary supplement makers: Be safe and legal. World Tea News. Web.
Chang, K. (2015). World tea production and trade current and future development. Report. Food and Agricultural Organization of the United Nations.
Green tea. (n.d.). The National Center for Complementary and Integrative Health. Web.
Tea and cancer prevention. (n.d.). The National Cancer Institute. Web.