Epidemiological studies in the Netherlands first demonstrated an inverse relationship between ordinary (technically known as black) tea drinking and cardiovascular disease (CVD) mortality. Subsequent population-based studies have variously agreed with, been opposite to (notably in the UK) or produced null results. Currently, UK epidemiological studies look out of step with the rest of the world. This review highlights that, in the UK, tea drinking is more pronounced in the lower socio-economic (SE) groups, whilst tea drinking is associated with higher SE groups in the other countries that have linked tea to CVD. It is this key difference that may account for the apparent positive relationship between tea drinking and CVD mortality in the UK; low SE status (and high tea drinking) is also strongly associated with a high prevalence of the major CVD risk factors.
Any positive benefits from tea drinking are likely to be due to a high content of antioxidant flavonoids, particularly the catechins. In vitro and intervention studies support mechanisms, such as improved endothelial function, whereby tea flavonoids may be cardioprotective.
Whilst there is no evidence from population studies of positive cardiovascular benefit from tea drinking in the UK, tea is still contributing flavonoids to individual diets and these may well be beneficial. Tea drinking can safely be encouraged as part of a healthy diet. Further studies are required to clarify the situation.
For UK healthcare professionals only