I don’t drink tea myself (don’t like it) but I do think that the evidence shows that it is actually quite a healthy beverage. Tea is rich in plant substances known as polyphenols which have been particularly linked with a reduced risk of heart disease. Not only that, but tea-drinking has also been associated in studies with a reduced risk of heart disease. Much of the research on tea and heart health has focused on black (regular) tea. However, green tea (from which black tea is made) is even richer in polyphenols. This has led some to consider whether green tea also has the capacity to protect against cardiovascular disease.
The potential for green tea to protect against cardiovascular disease was explored recently in a study published in the European Journal of Cardiovascular Prevention and Rehabilitation. The effects of green tea consumption was assessed in a group of 14 individuals aged about 30. Half of them were smokers, but otherwise they did not have any of the major risk factors for heart disease.
The chief measurement used in this study was ‘flow mediated dilatation’ (FMD) in one of the main arteries in the arm (the brachial artery). This measurement essentially tests the ability of arteries to relax, which is something that is obviously good for blood flow in the artery, and is associated with a reduced risk of cardiovascular disease risk.
The subjects in this study had their FMD measurements taken and then consumed beverages containing 6 g of green tea, 125 mg of caffeine (the amount of caffeine found in 6 g of green tea) or just plain hot water. When FMD was measured 30 mins later, it has improved significantly in those who had drunk the green tea, but this was not the case in individuals after consumption of caffeine or water.
The suggestion here is that one mechanism through which green tea may help to protect against cardiovascular disease risk is through an ability promote relaxation in the arteries. It also suggests that is not the caffeine in green tea that is having this effect.
Another foodstuff that is rich in polyphenols is coffee. It’s perhaps interesting to note that quite recent research has linked coffee consumption with a reduced risk of cardiovascular disease in women.
References:
Alexopoulos N, et al. The acute effect of green tea consumption on endothelial function in healthy individuals. European Journal of Cardiovascular Prevention & Rehabilitation. 2008;15(3):300-305
Green tea has also recently been shown to increase the effectiveness of antibiotics against bacteria & MRSA.
http://www.sciencedaily.com/releases/2008/03/080330200640.htm
I think there are a couple of slight inaccuracies here. First – though I haven’t counted – I have been following tea research for a number of years and I would say that more studies have been done on green tea than on black tea. See for example the studies mentioned at : http://www.jcm.co.uk/catalogue.php?catID=270&opener=0-197-270
Secondly, it’s not quite right to say that black tea is made from green tea, or rather it doesn’t quite convey the process. The same plant – the tea plant – produces both, although the sub-varieties may differ. Green tea is made by picking the leaves and drying them immediately. Black tea is made by letting the leaves sit (ferment/oxidise) before drying. Oolong teas are made using a shorted fermentation.
Peter
Green coffee bean extract has been found to be good for the heart and it also boosts metabolism.
Green tea with mint is nicer, especially if you have some mint fromt the garden to add to the pot. You shouldn’t let it brew for very long though. Alternatively, you can buy green tea supplement pills.