Written by Tatjana Djakovic, Staff Writer. Researchers found that systolic blood pressure decreased by 8.1% in study participants who drank hibiscus tea and their diastolic blood pressure decreased by 1.6%.
High blood pressure is a common condition that is often associated with other chronic conditions and is present in 1 in 3 adults. (1) Approximately 1 billion people worldwide and 74.5 million Americans are affected by high blood pressure. (2)
Hibiscus is an ingredient in many herbal teas and beverages and has antioxidant properties. Previous research in animal studies has demonstrated that it lowers cholesterol and blood pressure. The objective of a randomized, double-blind, placebo-controlled clinical study was to examine the effect of hibiscus tea on blood pressure in 65 non-smoking men and women aged 30-70 years, not taking blood pressure lowering medications.
The dosage given was 3 servings of 240ml of brewed hibiscus tea per day or a placebo beverage for 6 weeks. The blood pressure was measured at baseline and at weekly intervals. After 6 weeks, the hibiscus tea lowered systolic BP (pressure in arteries when the heart beats) compared with placebo by 5.5% (p=0.001), (from 129.4 to 122.3 mmHg) Diastolic pressure (pressure in arteries when heart is resting in between beats) was lowered by 4.0% (p=0.013).
In the placebo group, the systolic blood pressure did not decrease significantly it only dropped by less than one percent. (from 129.8 to 128.6 mmHg), and diastolic blood pressure also did not show a significant change (from 79.6 to 79.02 mm Hg). Participants that had a higher systolic blood pressure showed a greater response to hibiscus treatment. (3)
Another study has analyzed the effect of hibiscus tea on high blood pressure in diabetic patients. High blood pressure coexists with diabetes mellitus, and it contributes to a great extent to death in high risk population. The randomized controlled clinical trial was conducted with 60 diabetic patients. Participants were assigned to take either black tea or hibiscus tea, that were in similar in shape and weight and instructed to use one glass two times daily for 1 month. On days 1, 15, and 30 of the study, the patient’s blood pressure was measured by a physician.
The results of the study indicate that systolic blood pressure was decreased by 8.1% in the hibiscus group (from 134.4 to 112.7 mmHg), while the systolic blood pressure was increased by 6.2% (from 118.6 to 127.3 mmHg) (p<0.001) in the black tea group. The diastolic blood pressure decreased by 1.6% (from 81.6 to 80.5 mmHg) in the group taking hibiscus and it increased b 4.6% (from 76.7 to 80.0 mmHg) in the black tea group. (4)
The results of the two studies suggest that hibiscus can lower blood pressure which is of great value to many individuals that are at a risk for chronic conditions.
Source: Mozaffari-Khosravi, H., et al. “The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes.” Journal of human hypertension 23.1 (2009): 48-54.
© 2009 Macmillan Publishers Limited
Posted January 24, 2013.
References:
- Obtained from National Heart Lung and Blood Institute “Who is at Risk for High Blood Pressure?”
- Chen CC, Hsu JD, Wang SF, Chiang HC, Yang MY, Kao ES, Ho YC, Wang CJ. Hibiscus sabdariffa extract inhibits the development of atherosclerosis in cholesterol-fed rabbits. J Agric Food Chem.2003;51:5472–7.
- McKay, Diane L., et al. “Hibiscus sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults.” The Journal of nutrition 140.2 (2010): 298-303.
- Mozaffari-Khosravi, H., et al. “The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes.” Journal of human hypertension 23.1 (2008): 48-54.
