Hibiscus tea (Hibiscus sabdariffa L.) lowers blood pressure in pre- and mildly hypertensive adults.

Changes in diet and physical activity are recommended for individuals with pre-hypertension and mild Stage I hypertension. Hibiscus sabdariffa calyces are a common ingredient in tisane (herbal tea) blends sold in the U.S. Water extracts of hibiscus possess antioxidant properties in vitro, and produce anti-hypertensive and hypocholesterolemic effects in animal models. To determine whether consuming hibiscus tisane in an amount readily incorporated into the diet (3 c/d containing ∼9.4 mg total anthocyanins) can lower blood pressure (BP) in humans, we conducted a 6 wk randomized, double-blind, placebo-controlled clinical trial in pre- or mildly hypertensive adults (35-70 y; n=13 >50 y) with a systolic BP of 120-150 mm Hg and diastolic BP of ≤95 mm Hg. Exclusions include use of antihypertensive medication, chronic disease, or history of smoking. Repeated measures ANOVA of data obtained during weekly visits of the first 20 subjects (50% female) indicate a lowering of systolic BP with hibiscus treatment among females (P=0.023) and subjects >50 y (P=0.039) when compared to the placebo beverage with artificial flavoring and color. These preliminary data support the hypothesis of a BP lowering action of hibiscus tea, though conclusions may be drawn only with completion and analysis of the full protocol sample size (n=74) with 80% power to detect a change in BP at the P≤0.05 level. [ABSTRACT FROM AUTHOR]