Fleurs d'Hibiscus: une tisane pour hypertendus

La tisane de fleur d'hibiscus est un antihypertenseur modéré qui mérite d'être cité car ses effets secondaires sont nuls.
Une étude randomisée contre placébo récente l'atteste. S'agit-il de la richesse en anti-oxydants ou bien d'autres propriétés plus spécifiques ?
Les auteurs lient ce résultat au contenu en polyphénols et en particulier en flavonoïdes de la tisane de fleurs d'hibiscus.

Référence
Nutrition and Disease
Hibiscus Sabdariffa L. Tea (Tisane) Lowers Blood Pressure in Prehypertensive and Mildly Hypertensive Adults1–4,
Diane L. McKay5,*, C-Y. Oliver Chen5, Edward Saltzman6 and Jeffrey B. Blumberg5

5 Antioxidants Research Laboratory; 6 Energy Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111

In vitro studies show Hibiscus sabdariffa L., an ingredient found in many herbal tea blends and other beverages, has antioxidant properties, and, in animal models, extracts of its calyces have demonstrated hypocholesterolemic and antihypertensive properties. Our objective in this study was to examine the antihypertensive effects of H. sabdariffa tisane (hibiscus tea) consumption in humans. A randomized, double-blind, placebo-controlled clinical trial was conducted in 65 pre- and mildly hypertensive adults, age 30–70 y, not taking blood pressure (BP)-lowering medications, with either 3 240-mL servings/d of brewed hibiscus tea or placebo beverage for 6 wk. A standardized method was used to measure BP at baseline and weekly intervals. At 6 wk, hibiscus tea lowered systolic BP (SBP) compared with placebo (–7.2 ± 11.4 vs. –1.3 ± 10.0 mm Hg; P = 0.030). Diastolic BP was also lower, although this change did not differ from placebo (–3.1 ± 7.0 vs. –0.5 ± 7.5 mm Hg; P = 0.160). The change in mean arterial pressure was of borderline significance compared with placebo (–4.5 ± 7.7 vs. –0.8 ± 7.4 mm Hg; P = 0.054). Participants with higher SBP at baseline showed a greater response to hibiscus treatment (r = –0.421 for SBP change; P = 0.010). No effects were observed with regard to age, gender, or dietary supplement use. These results suggest 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 with these conditions.

* To whom correspondence should be addressed: diane.mckay@tufts.edu