First study of its kind
A Unilever study has shown, for the first time, that drinking black tea may significantly reduce your blood pressure which, in turn, could lessen the risk of stroke and heart disease.
The study, carried out by Unilever R&D in collaboration with the University of Western Australia and the National Health and Medical Research Council of Australia, was designed to examine the long-term cardiovascular effects of regular consumption of tea-derived flavonoids.
Three cups a day
The clinical trial took six months to complete. During that time, 100 mildly hypertensive participants – those with slightly raised blood pressure – were asked to drink either three cups of Lipton Yellow Label black tea a day or three cups of a caffeinated, flavoured and coloured placebo drink.
The participants’ blood pressure was measured at the start of the study, after three months of consuming the drinks and then again after six months.
Small but important change
Analysis of the results showed that the Lipton Yellow Label tea drinkers had lower systolic and diastolic* blood pressures at three and six months compared with those who had drunk the placebo. Blood pressures were on average 2–3mmHg** lower in the tea drinking group.
Although this reduction is small, it is significant, particularly when viewed across a whole population. More than a billion people in the world drink tea and it is the second most consumed drink in the world after water.
According to Jane Rycroft, Senior Nutrition and Health Manager, Unilever R&D: “This is a hugely exciting development for us. It is further evidence to suggest that tea and its natural ingredients can help people become healthier.
“While a 2–3mmHg decrease is a small change to an individual’s blood pressure, it’s tantalising to think what positive impact this could have on reducing the risk of heart disease among the general public.”
The evidence is mounting
More research is required to understand better how tea can reduce blood pressure, although earlier studies by the same Unilever team at Vlaardingen reported a potential link between tea consumption and the improved health of human blood vessels.
*When your heart beats, it contracts and pushes blood through the arteries to the rest of your body. This force is called systolic blood pressure. Diastolic blood pressure indicates the pressure in the arteries when the heart rests between beats.
**mmHg (millimetres of mercury) is the unit used to measure blood pressure.