November 10, 2008 -Drinking hibiscus tea lowered blood
pressure in a group of pre-hypertensive and mildly hypertensive adults,
according to a report being presented today by nutrition scientist
McKay at the
Heart Association's annual conference in New Orleans, La. Hypertension is a
condition in which blood pressure is chronically high, and it affects one-third
of all U.S. adults.
McKay's research was funded by the Agricultural Research Service (ARS), a
scientific research agency of the U.S.
Department of Agriculture (USDA), and by Boulder, Colo.-based
Celestial Seasonings, a brand
of The Hain Celestial Group, Inc.
McKay works in the
Research Laboratory of the
Mayer USDA Human Nutrition Research Center on Aging at
Tufts University in Boston, Mass.
In a clinical trial, McKay tested 65 volunteers, aged 30 to 70 years, whose
systolic blood pressure was 120 to 150 mm Hg and whose diastolic blood pressure
was 95 mm Hg or less at the start of the study. Blood pressure readings of 120
over 80 or greater are considered a risk factor for heart disease, stroke and
For six weeks, about half the group was randomly selected to drink three
cups of hibiscus tea daily. The others drank a placebo beverage containing
artificial hibiscus flavoring and color. All participants were advised to
follow their usual diet and maintain their normal level of activity. Before the
start of the study, blood pressure was measured twice, one week apart, and at
weekly intervals thereafter.
The findings show that the volunteers who drank hibiscus tea had a 7.2 point
drop in their systolic blood pressure, compared to a 1.3 point drop in the
volunteers who drank the placebo beverage.
In a subgroup analysis, 30 volunteers with the highest systolic blood
pressure readings at the start of the study (129 or above) were found to have a
greater response to hibiscus tea drinking compared to placebo drinkers. Their
systolic blood pressure went down by 13.2 points, diastolic blood pressure went
down by 6.4 points, and mean arterial pressure went down by 8.7 points.
This data supports the idea that drinking hibiscus tea in an amount readily
incorporated into the diet may play a role in controlling blood pressure,
although more research is required.