Dr. Diane McKay of the Jean Mayer USDA Nutrition Research Center on Aging, Tufts University Boston, MA, reported to the American Heart Association in 2008 the results of her study on the use of hibiscus tea to lower high blood pressure. This was a randomized, double blind placebo controlled trial.
Participants consumed 3 cups of hibiscus tea daily for 6 weeks versus a group that consumed a placebo beverage. The trial included 65 men and women aged 30 to 70 whose blood pressure ranged from 120-150 systolic and less than 95 diastolic. See my earlier post for an explanation of systolic and diastolic measurements.
None of the subjects were on high blood pressure medications. The blood pressure reduction achieved is listed in the following table.
Blood Pressure Reduction
The following were the results:
| Systolic | Diastolic | |
|---|---|---|
| Hibiscus Tea (3 8oz. cups daily) | 7-13 points | 3 points |
| Placebo Group | 1 point | 0.5 points |
| Avg. Blood Pressure Medication | 5-9 points | 3-5 points |
The average systolic blood pressure reduction was 7 points; however, in those with systolic blood pressures over 129, the average systolic blood pressure reduction was slightly more than 13 points. This exceeds the average reduction achieved by a blood pressure medication of 5-9 points systolic.
A Possible Explanation
Dr. McKay said that the presence of anthocyanins as well as other phytonutrients in the hibiscus tea could have contributed to the significant outcome. The placebo beverage contained no anthocyanins. These substances act in a manner similar to a class of high blood pressure medications called ACE inhibitors.
In another study comparing hibiscus tea against Captopril (a widely used ACE inhibitor), hibiscus tea proved to be equally as effective as the medication in lowering high blood pressure.
More Dramatic Blood Pressure Reduction
The Journal of Human Hypertension (August 2008) published a study in which hibiscus tea was compared to black tea in a group of diabetic patients. This group included 60 diabetic patients (Type 2 Diabetes). None of the group were on high blood pressure medications. For a period of one month, one group drank 2 cups of hibiscus tea while the other drank 2 cups of black tea.
The hibiscus tea group went from a systolic blood pressure of 134 to a systolic blood pressure of 112. There was no statistically significant difference in diastolic blood pressure. The authors conclude that their study confirms what other studies have found: hibiscus tea has an antihypertensive impact.
Questions and Cautions
There have been some questions raised regarding drinking hibiscus tea while pregnant. Dr. McKay indicated that in Nigeria, parts of the population consume the equivalent of 25 cups of hibiscus tea per day with no reported side effects. As always, if you are taking medication or considering a change in diet, consult with a licensed health practitioner.
Enjoy your hibiscus tea, and tell us your favorite natural snack that goes with it!
References
- Dr. Diane L. McKay discusses findings that drinking hibiscus tea can reduce systolic blood pressure (video from Elsevier Global Medical News)
- The Peoples Pharmacy: Hibiscus Tea Provides Amazing Blood Pressure Control
- Journal of Human Hypertension: The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes
