Black tea may help reduce nighttime fluctuations in blood pressure, according to an Australian study published in the American Journal of Clinical Nutrition in May.
For six months, 111 people (ages 35 to 75) drank three cups a day of either black tea or a placebo beverage, which looked like tea and contained the same amount of caffeine. The tea drinkers experienced an immediate and sustained reduction in blood pressure variability at night, but not during the day.
Prior research has found that tea can lower blood pressure slightly; however, the reduction in variability seen in the new study was independent of any effect on blood pressure itself.
There’s increasing evidence that blood pressure variability is a risk factor for cardiovascular disease. The researchers attributed this benefit to the flavonoids in the tea.