Tea and Its Consumption: Benefits and Risks

Abstract

The recent convention of introducing phytochemicals to support the immune system or combat diseases is a centuries' old tradition. Nutritional support is an emerging advancement in the domain of diet-based therapies; tea and its constituents are one of the significant components of these strategies to maintain the health and reduce the risk of various malignancies. Tea is the most frequently consumed beverage worldwide, besides water. All the three most popular types of tea, green (unfermented), black (fully fermented), and oolong (semifermented), are manufactured from the leaves of the plant Camellia sinensis. Tea possesses significant antioxidative, anti-inflammatory, antimicrobial, anticarcinogenic, antihypertensive, neuroprotective, cholesterol-lowering, and thermogenic properties. Several research investigations, epidemiological studies, and meta-analyses suggest that tea and its bioactive polyphenolic constituents have numerous beneficial effects on health, including the prevention of many diseases, such as cancer, diabetes, arthritis, cardiovascular disease (CVD), stroke, genital warts, and obesity. Controversies regarding beneficialts and risks of tea consumption still exist but the limitless health-promoting benefits of tea outclass its few reported toxic effects. However, with significant rise in the scientific investigation of role of tea in human life, this review is intended to highlight the beneficial effects and risks associated with tea consumption.

Association of green tea consumption with mortality from all-cause, cardiovascular disease and cancer in a Chinese cohort of 165,000 adult men

“…Green tea is rich in catechin polyphenols in which catechins (epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate) and flavanols represent 80-90 and \10 % of total flavonoids, respectively [9]. With more than 4000 chemical compounds, green tea is hypothesized to have beneficial effects for maintaining health and reducing the risk of various diseases [1,[10][11][12].…”

“…It originated from China, known as the ''Divine Healer,'' almost 5000 years ago and is currently being cultivated in more than thirty countries worldwide [1][2][3][4]. In 2010, the Chinese population consumed the equivalent weight of 1,360,060 tons in tea leaves [5].…”

An Update on the Health Benefits of Green Tea

“…Black tea (around 78% of tea production) is mostly consumed in the United States and the United Kingdom. Black tea contains up to three times the amount of caffeine as green tea [3][4][5].…”

“…Black tea leaves are dried, then rolled and crushed, which promotes oxidation. Therefore, black tea has far fewer active catechins than green tea [1,2,5,8]. Green tea contains four main catechins: (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin-3-gallate (ECG), and (−)-epigallocatechin-3-gallate (EGCG).…”

“…Table 1 shows a summary of the results of some of these studies. black tea has far fewer active catechins than green tea [1,2,5,8]. Green tea contains four main catechins:…”