Acute Effect of Black and Green Tea on Aortic Stiffness and Wave Reflections

Abstract

Both black and green tea increases acutely wave reflections and only black tea increases aortic stiffness. Tea flavonoids may play a role in the attenuation of the effects of caffeine contained in tea.

Scientific Opinion on the substantiation of health claims related to Camellia sinensis (L.) Kuntze (tea), including catechins in green tea and tannins in black tea, and protection of DNA, proteins and lipids from oxidative damage (ID 1103, 1276, 1311, 1708, 2664), reduction of acid production in dental plaque (ID 1105, 1111), maintenance of bone (ID 1109), decreasing potentially pathogenic intestinal microorganisms (ID 1116), maintenance of vision (ID 1280), maintenance of normal blood pressure (ID 1546) a

“…Four human intervention studies (Kim et al, 2006;Duffy et al, 2001;Vlachopoulos et al, 2006;Nagaya et al, 2004) and three human observational studies (Hodgson et al, 2003;Stensvold et al, 1992;Yang et al, 2004) investigating the effects of tea on measurements of BP were cited for the substantiation of the claimed effect.…”

Role of green tea in reduction of cardiovascular risk factors

“…1 The concentration of caffeine in a tea beverage largely depends on the same parameters as those described for flavonoids; it is estimated that tea typically contains 40-60 mg of caffeine per cup (175 ml), whereas coffee typically contains 65-100 mg of caffeine per 175 ml. 8 Although there is great variability, there is usually less caffeine in green tea than in black tea, 1,9 Green tea consumption and cardiovascular events Cardiovascular mortality…”

“…Acutely, green tea increases blood pressure, as has been repeatedly shown. 9,21,22 One of the ingredients in tea with an acute pressor effect is caffeine, 23,24 however, the acute rise in blood pressure after tea consumption is greater than that of the same amount of caffeine ingested alone. It is not known which other tea ingredients are responsible for this.…”

“…23,[95][96][97] In a study where the acute effect of green tea consumption was compared to that of its caffeine content, it was shown that green tea had a neutral effect on arterial stiffness and it slightly increased wave reflections, whereas the effect of its caffeine content alone (ingested as caffeine capsules) was more prominent and more sustained (Figure 4). 9 Unpublished data suggest that the short-term (2 weeks) effect of green tea consumption on arterial stiffness may be beneficial. 98 The finding that flavonoid-rich foods with low or absent xanthine content reduce arterial stiffness and wave reflections implies that green tea catechins may account for the neutral effect of green tea on arterial stiffness and for its possibly beneficial short-term effect.…”

Scientific Opinion on the substantiation of health claims related to Camellia sinensis (L.) Kuntze (tea), including catechins in green tea, and improvement of endothelium-dependent vasodilation (ID 1106, 1310), maintenance of normal blood pressure (ID 131

“…Among the human intervention studies which investigated the effects of green tea or green tea catechins on endothelium-dependent vasodilation (assessed as brachial-ankle pulse wave velocity, PWV), two were acute studies which did not address the sustained effects of chronic consumption of the food (Nagaya et al, 2004;Vlachopoulos et al, 2006), three s were uncontrolled (one arm) interventions Murakami and Ohsato, 2003;Sung et al, 2005), and was a one randomised controlled trial (Ryu et al, 2006) in which green tea was not sufficiently characterised in relation to the claimed effect (e.g. amount of catechins not reported).…”