|Chen, C-y. Oliver|
Submitted to: Circulation
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2008
Publication Date: 10/28/2008
Citation: Mckay, D.L., Saltzman, E., Chen, C., Blumberg, J. 2008. Hibiscus sabdariffa L. tea (Tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. Circulation. 118:S-1123.
Technical Abstract: Introduction: In vitro studies have shown Hibiscus sabdariffa L., an ingredient of many herbal tea blends and other beverages, has antioxidant properties. In animal models, extracts of hibiscus calyces possess hypocholesterolemic and anti-hypertensive properties. Hypothesis: We hypothesized that daily consumption of H. sabdariffa tisane (hibiscus tea) has a beneficial effect on blood pressure (BP) in pre- and mildly hypertensive adults. Methods: A double-blind, placebo-controlled clinical trial was conducted in 65 men and women, age 30-70 y, with systolic BP (SBP) 120-150 and diastolic BP (DBP) less than or equal to 95 mm Hg, who were not on BP-lowering medications. Subjects were randomized to receive either 3 c/d hibiscus tea (brewed from 3.75 g of plant material) or a placebo beverage for 6 wk. A standardized method was used to measure BP at 2 baseline visits, 1 wk apart, and at weekly intervals thereafter. Results: H. sabdariffa treatment lowered SBP (mean +/- SEM) compared with placebo (-7.2 +/- 1.9 vs. -1.3 +/- 1.8 mm Hg, P <0.03). DBP was also lower after treatment, although this change was not significantly different than placebo (-3.1 +/- 1.2 vs. -0.5 +/- 1.4 mm Hg, P=0.16). The decrease in mean arterial pressure (MAP) was of borderline significance (-4.5 +/- 1.3 vs. -0.8 +/- 1.4 mm Hg, P=0.054). No interactions were observed with regard to age, gender or use of dietary supplements. In a subgroup analysis, subjects with higher SBP at baseline (>129 mm Hg, n=30) showed a greater response to H. sabdariffa treatment when compared with placebo for SBP (-13.2 +/- 2.9 vs. -1.3 +/- 3.4 mm Hg, P=0.012), DBP (-6.4 +/- 1.4 vs. 1.3 +/- 1.8 mm Hg, P=0.002), and MAP (-8.7 +/- 1.6 vs. 0.4 +/- 2.1 mm Hg, P=0.002). Conclusions: Daily consumption of hibiscus tea, in 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.