More hints for the beneficial effect of green tea on risk factors for heart disease has emerged. The study was a randomised trial involving the diameter measurement (dilatation) of the brachial artery of healthy volunteers on three separate occasions - after taking green tea, caffeine, and hot water for a placebo effect.
The measurements were taken at 30, 90 and 120 minutes after consumption. Dilatation of the brachial artery as a result of increased blood flow (following a brief period of ischaemia of the upper limb) is related to endothelial function and is known to be an independent predictor of cardiovascular risk.
Results showed that endothelium-dependent brachial artery dilatation increased significantly after drinking green tea, with a peak increase of 3.9 per cent 30 minutes after consumption. The effect of caffeine consumption, or hot water, was not significant, according to the scientists.
Green tea, which originates in China but is now consumed throughout the world, is made with pure leaves, and has undergone little oxidisation during processing. The cardiovascular benefits of all teas - as well as dark chocolate and red wine - are attributed to the flavonoids they contain and their antioxidant activity. However, says investigator Doctor Charalambos Vlachopoulos, flavonoids in green tea are probably more potent antioxidants than in black tea because there has been no oxidisation.
MEDICA.de; Source: European Society of Cardiology