Moderate Intake of Flavonoid-Rich Tea, Green or Black, Confers Cardiovascular Protection
Keywords:green tea, black tea, flavonoids, catechins, cardiovascular disease, cardiovascular protection, hypertension
A variety of dietary supplements have been proposed for the management of hypertension and other cardiovascular diseases, but the evidence for their efficacy is meagre.1 However, over the last few years, there is growing interest in the potential benefit of tea in cardiovascular protection.2-4 Tea is the extract of Camellia sinensis, and one of the most widely enjoyed drinks.2,3 The leaves of the plant are rich in flavonoids, containing several phytochemicals including phenols and catechins, to which potent antioxidant, free radical scavenging, appetite-modifying and hypolipidemic effects have been ascribed.2-7 Long-term consumption of beverages containing catechins inhibits the formation of oxidized lipids and decreases body fat.5-9 Over 70% of flavonoids in green tea are catechins. Epigallocatechin-3-gallate (EGCG) is the cardinal (65%) catechin in green tea. In-vitro studies have shown that the epigallocatechins in green tea have angiotensin converting enzyme inhibitor properties,10 and vasodilatory actions. 11 Molecular and animal studies have demonstrated that green tea catechins enhance processes, thought to stimulate bile acid production, decrease cholesterol concentration in the hepatocytes, inhibit intestinal absorption of lipids and upregulate low-density lipoprotein (LDL) receptors in the liver, mechanisms all leading to favorable blood lipid profile.2-4,12,13
Black tea also contains small amounts of catechins. However, due to the fermentation process of black tea, its primary antioxidant polyphenols are theaflavins and thearubigins, equally effective antioxidants to catechins. 14... (excerpt)
LicenseAuthors who publish with this journal agree to the following terms:
a. Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
b. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
c. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).