Emerging evidence for tea benefits

Abstract

Summary Tea is the most commonly consumed beverage in the world, after water. Associations between regular tea drinking and a reduced risk of coronary heart disease are well established. The mechanism may relate to bioactive compounds found in tea, which exert anti‐arteriosclerotic, anti‐oxidative and anti‐inflammatory effects. However, evidence for other diverse health benefits is emerging. The aim of this review was to evaluate research on three new areas of interest in relation to tea drinking: (1) weight management (and glycaemic control); (2) oral health; and (3) gut health. Databases were searched for meta‐analytical, human intervention and epidemiological studies published between 1990 and 2013. For weight management, modest, positive effects were found for green tea when ingested by overweight/obese adults, possibly related to thermogenic effects. Epidemiological studies indicate that tea drinking in general may protect against tooth loss, certain oral/digestive cancers and Helicobacter pylori infection, although the studies were few in number with differing methodologies. A growing body of mechanistic studies suggests that tea has anti‐cariogenic, anti‐adhesive, anti‐bacterial and possible pre‐biotic effects – all with the potential to impact positively on the pathogenesis of chronic diseases. Clearly, larger trials are needed to confirm these effects in humans and establish optimal intakes. In the meantime, tea drinking appears to be a simple and beneficial way to support health.

Fluoride content of retail tea bags and estimates of daily fluoride consumption from typical tea drinking in UK adults and children

“…Interestingly, other studies have suggested that tea consumption may support oral health (see Ruxton for a review). The mechanisms are thought to relate to the antimicrobial and antioxidant effects of tea flavonoids, which inhibit the adhesion and growth of bacteria (Hamilton‐Miller ).…”

“…Tea drinking has also been associated with other health benefits including reduced risk of cardiovascular disease, colorectal cancer and type 2 diabetes (Gardner et al . ; Ruxton ). In addition, tea compares favourably with water as a means of supporting normal hydration levels even with a caffeine content of 40–50 mg per serving (Ruxton & Hart ).…”

“…The mechanisms are thought to relate to the antimicrobial and antioxidant effects of tea flavonoids, which inhibit the adhesion and growth of bacteria (Hamilton-Miller 2001). Tea drinking has also been associated with other health benefits including reduced risk of cardiovascular disease, colorectal cancer and type 2 diabetes (Gardner et al 2007;Ruxton 2013). In addition, tea compares favourably with water as a means of supporting normal hydration levels even with a caffeine content of 40-50 mg per serving (Ruxton & Hart 2011).…”

Effect of freezing treatment in tea preparation using Camellia sinensis leaves

“…Tea is generally prepared by treating C. sinensis leaves through heating (roasting, steaming), wilting, rolling, fermentation, and drying (Kim et al 2009). The raw material remains the same but it acquires different flavors and health functionalities according to the kind of treatment and degree of application of the processing method (Yang and Liu 2013;Ruxton 2013;Jo et al 2006). Among these different types of tea, green tea is unfermented tea prepared by intensive application of heat treatment to prevent oxidation, by deactivating enzymes in tea leaves and preserving the green color.…”

Preservation of specificity of phenolic compounds accumulation in in vitro cultures initiated from various tea plant organs (Camellia sinensis (L.) O. Kuntze)

“…Из его листьев получают один из самых популярных в мире и широко потребляемых напитков, обладающий не только приятным вкусом и ароматом, но и целебными свойствами. Он оказывает стимулирующее действие на нервную систему, снижает риск развития сахарного диабета, инсульта, сердечно-сосудистых и онкологических заболеваний [18][19][20].…”