Tea and Cardiovascular Disease
Cardiovascular Disease (CVD) is the main cause of death in many western countries, accounting for hundreds of thousands of deaths each year, more than one in three people. The main forms of CVD are Coronary Heart Disease (CHD) and stroke. About half of all deaths from CVD are from CHD and about a quarter are from stroke.
The benefits of tea
There is growing evidence suggesting that other dietary components may enhance the general healthy eating recommendations. For example, research is highlighting that there maybe a beneficial relationship between tea drinking and reduced risk of cardiovascular disease.
The evidence for tea and CVD
A number of epidemiological studies have demonstrated that total flavonol/ flavonoid or tea consumption is linked to protection from heart disease and stroke. However, not all studies have shown similar protective effects. Inconsistencies from these studies maybe as a result of their design e.g. lack of detail about exposure to tea – quantity, strength and variety, insufficient information about the flavonoid contents of foods and other risk factors for CVD not being considered. These details may influence the end results and consideration of these factors is required for any future research. However, the conclusions from a recent meta-analysis of all studies investigating the relationship between tea drinking and CHD suggested that drinking 3 cups of tea a day reduces the risk of myocardial infarction by 11%.
Protective mechanisms of tea
The outcomes from these studies have created great interest in understanding the mechanisms by which tea may confer its cardiovascular protective properties. Mechanisms such as the prevention of LDL oxidation, reduction in blood lipids,
anti-inflammatory actions, improvements in blood vessel function29 and inhibition of platelet aggregation have been established mainly in animal and in vitro studies. These mechanisms are discussed in greater detail on the Tea and Antioxidants page.
Results in human studies are not as clear, and although some epidemiological studies seem to indicate that tea can reduce serum cholesterol8, most studies show no effect in reducing serum cholesterol or blood pressure. As antioxidant activity from tea has been demonstrated in vivo, it may be that tea exerts its cardioprotective properties in other ways such as improvements in endothelial dysfunction, platelet aggregation or ways that have yet to be investigated.
From a number of epidemiological studies investigating the relationship between tea drinking and cardiovascular disease, it is reasonable to conclude that drinking both green and black tea is compatible with dietary advice to help protect against CVD.
However, although the scientific evidence for the mechanisms by which tea exerts its positive health effects is growing, it is not yet conclusive and represents promising areas for future research in human trials.
Nutritional Value | Tea and the fight against Cancer | Oral Health | Tea and Caffeine | Hydration | Tea and antioxidants |
Black and Green Tea
Tea and Cardiovascualar Disease (CVD) | Iron Absorption