by Heidi Kyser 

A recent clinical trial indicates that regular consumption of hibiscus tea may help those at risk of developing hypertension to lower their blood pressure.

Diane L. McKay, Edward Saltman, Chung-Yen Chen and Jeffrey B. Blumberg conducted the study through Tufts University's Human Nutrition Research Center on Aging.

Departing from previous in-vitro and animal studies that have indicated the herb Hibiscus sabdariffa has antioxidant and anti-hypertensive properties, the team "hypothesized that daily consumption of H. sabdariffa tisane (hibiscus tea) has a beneficial effect on blood pressure (BP) in pre- and mildly hypertensive adults," according to an abstract of the work.

The researchers selected a group of 65 of these pre- and mildly hypertensive adults, ages 30 to 70, for a double-blind, placebo-controlled clinical trial. They split the subjects into two groups and, over a six-week period, gave one group three cups of hibiscus tea per day and the other a placebo, "essentially a flavored water containing artificial hibiscus flavoring and color," McKay told WSN.

The group that drank the hibiscus tea experienced a decrease in mean systolic blood pressure of 7.2; the two groups experienced approximately the same drop in diastolic blood pressure. When the results were examined by sub-groups, however, they indicated that the effects of drinking hibiscus tea were greater across the board among subjects whose systolic blood pressure was higher to begin with.

The overall conclusion? "Daily consumption of three cups of hibiscus tea, an amount readily incorporated into the diet, lowers BP in pre- and mildly hypertensive adults and may prove an effective component of the dietary changes recommended for people at risk of developing hypertension."

McKay said this was not the first study of hibiscus in humans, but it was the first placebo-controlled trial. She added, "It was also the first study conducted in generally healthy people (with mildly elevated blood pressure) who were not already taking any blood pressure-lowering medications."

McKay said she wasn't really surprised by the results, because of previous, related research. But, she added, "we weren't sure if we would see the degree of change that we did with such a reasonable dose. It is also interesting to note that our subjects were told to consume their usual diet, and not change their level of physical activity for the duration of the study."