MILAN, Italy — A large French retrospective analysis provides good news for caffeine lovers: investigators showed that drinking tea or coffee was associated with a small but statistically significant reduction in systolic and diastolic blood pressure. In addition, drinking tea and coffee was also associated with a significant reduction in pulse pressure and heart rate, although the heart-rate reductions were greater with tea.
Presenting the results at the European Society of Hypertension (ESH) 2013 Scientific Sessions, Dr Bruno Pannier (Centre d’Investigations Préventives et Cliniques, Paris, France) said that other studies have suggested a relationship between coffee and tea consumption and blood pressure, but these analyses haven’t been conclusive. Some have suggested a benefit, while others found no relationship between tea/coffee consumption and blood pressure.
Presenting the data on 176 437 subjects aged 16 to 95 years of age who had a checkup at their center between 2001 and 2011, Pannier explained that the analysis was simply based on a questionnaire asking participants how much coffee or tea they drank per day. Individuals were classified into three groups: those who drank no coffee/tea, those who drank one to four cups, and those who drank more than four cups.
Overall, coffee is consumed more frequently than tea, although there were differences between the sexes, said Pannier. Men were more likely to drink coffee, while women were more commonly tea drinkers. Coffee consumption was also significantly associated with tobacco consumption, higher cholesterol levels, and higher scores on stress and depression indexes. Tea consumption, on the other hand, was associated with lower cholesterol levels but similarly high scores on the stress and depression measurements.
After adjustments that included these and other potential confounding variables, both coffee and tea consumption was associated with a significant reduction in systolic and diastolic blood pressure, as well as other variables.
Blood Pressure Among Coffee Drinkers
| Variable | None | 1 to 4 cups | >4 cups | p (for trend) |
| Systolic blood pressure (mm Hg) | 127.9 | 126.7 | 125.5 | <0.0001 |
| Diastolic blood pressure (mm Hg) | 76.0 | 76.0 | 75.7 | 0.02 |
| Pulse pressure (mm Hg) | 51.9 | 50.7 | 49.8 | <0.0001 |
| Heart rate (beats/min) | 63.2 | 62.9 | 63.2 | 0.001 |
Blood Pressure Among Tea Drinkers
| Variable | None | 1 to 4 cups | >4 cups | p (for trend) |
| Systolic blood pressure (mm Hg) | 127.3 | 126.3 | 125.3 | <0.0001 |
| Diastolic blood pressure (mm Hg) | 76.2 | 75.6 | 75.0 | <0.0001 |
| Pulse pressure (mmHg) | 51.1 | 50.7 | 50.3 | <0.0001 |
| Heart rate (beats/min) | 63.5 | 62.7 | 62.0 | <0.0001 |
Speaking during the session, Pannier explained that the group did not differentiate between green, black, or herbal tea consumption, which is one of the limitations of the analysis. In addition, the questionnaire is not sophisticated enough to address estimates in the caffeine content of the coffee consumed in France.
That said, Pannier believes that tea is a major source of flavonoids in the diet, and these compounds can improve vasodilation. “The vasorelaxing compounds included in these beverages might be involved in these results, something that has been suggested by the experimental data,” he said.
— Michael O’Riordan
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