NEW YORK (Reuters Health) – A study in Australia suggests that drinking black tea throughout the day would provide an extra benefit: a slight decrease in blood pressure.
Although the research does not identify the compounds in tea responsible for this effect, the authors note that previous studies had indicated the cardiac benefits of flavonoids found in many plants, including tea.
The study, published in Archives of Internal Medicine, the authors divided into two groups at 95 Australians with normal pressure. One group drank black tea and the other a drink with the same taste and caffeine content.
Before the study, participants daytime blood pressure was 121/72 mm Hg.
The values of up to 120/80 mm Hg are normal, but when they exceed 140/90 indicate hypertension. The range between the two values is considered “prehypertension”.
Each group ingested the assigned drink three times a day for six months.
At the end of the experiment, the systolic (maximum) of tea drinkers was 2 mm Hg lower. Diastolic pressure also fell about 2 mm Hg.
Any decrease in pressure is good, but 2 mm Hg are not significant enough to rid the area of risk to a person with high blood pressure.
“They are small or insignificant changes when compared with the effect of an antihypertensive,” said Dr. Joseph Vita, Faculty of Medicine, Boston University, who did not participate in the study.
However, the systolic pressure in the control group increased by 1 mm Hg, while diastolic pressure did about 0.5 mm Hg.
To rule out the influence of other foods, all participants reduced their consumption of flavonoid-rich foods such as apples, grapes, chocolate and wine for four weeks before and during the study.
Hodgson noted that such a dietary change could have caused the increased pressure in the control group.
The study was conducted with public subsidies and the area of Research and Development Unilever, which markets the Lipton tea brand.