EFFECTS OF TEA AND TEA FLAVONOIDS ON ENDOTHELIAL FUNCTION AND BLOOD PRESSURE: A BRIEF REVIEW
Presented at a symposium in honour of Lawrie Beilin held in conjunction with the High Blood Pressure Research Council of Australia Annual Scientific Meeting, Melbourne, 6–7 December 2005. The papers in these proceedings have been peer reviewed.
Dr Jonathan Hodgson, School of Medicine and Pharmacology, University of Western Australia, PO Box X2213, Perth, WA 6847, Australia. Email: Jonathan.Hodgson@uwa.edu.au
- 1The consumption of tea worldwide is second only to water. Thus, any physiological effects of tea could have a significant impact on population health.
- 2Tea is the major contributor to total flavonoid intake in many populations. Flavonoids in tea have been shown to have a range of activities and effects that could contribute to improved health. Tea intake and the intake of flavonoids found in tea have been associated with reduced risk of cardiovascular disease in several cross-sectional and prospective population studies. A variety of possible mechanisms have been investigated. The focus of the present review is on the mounting evidence that tea flavonoids can improve endothelial function and lower blood pressure.
- 3In vitro studies using isolated vessels have shown that tea flavonoids possess vasodilator activity. Results of human intervention trials have shown that increased flavonoid intake from tea, as well as other dietary sources, can improve endothelial function. Emerging data also suggest that the degree of benefit may be related to flavonoid metabolism.
- 4The effects of tea flavonoids on blood pressure are less consistent. Results of animal studies and population studies are consistent with a blood pressure-lowering effect of tea. However, short-term intervention trials, mainly in normotensive individuals, have not demonstrated any blood pressure reduction with tea.
- 5Overall, the available data suggest that the effects of tea flavonoids on endothelial function and, perhaps, blood pressure may be responsible, at least in part, for any benefits of drinking tea on the risk of cardiovascular disease.