Effects of the consumption of proanthocyanidins derived from acacia bark on blood pressure in healthy Japanese adults: A randomized, double-blind, placebo-controlled, parallel-group comparison study

Abstract

Objective: The aim of this study is to verify the effects of consuming proanthocyanidins derived from acacia bark on improving blood pressure and blood circulation in healthy Japanese adult subjects. Methods: This was a randomized, double-blind, placebo-controlled, parallel-comparison study involving 66 healthy Japanese adults. Subjects were allocated into either acacia or placebo group (n = 33 each) using a random number generator. Subjects consumed six tablets/day of either acacia bark extract tablets or placebo for 12 weeks. The primary outcome was the measured value of sitting systolic blood pressure at 12 weeks, whereas the secondary outcomes were sitting systolic and diastolic blood pressures, superoxide dismutase activity in blood, and blood flow.Results: The number of subjects analyzed as full analysis set was 33 (20 men and 13 women) in the Acacia group and 31 (23 men and 8 women) in the placebo group. Compared with the placebo group, the measured values and changes from baseline at 4, 8, and 12 weeks of the sitting systolic blood pressure were significantly lower in the Acacia group. Furthermore, “the ratio of the number of subjects whose sitting systolic blood pressure <130 mmHg and diastolic blood pressure ≤89 mmHg at 12 weeks” of the Acacia group was significantly higher than that of the placebo group. No adverse event was observed. Conclusions: Proanthocyanidins derived from acacia bark showed a hypotensive effect. Trial registration: UMIN-CTR: UMIN000039416. Foundation: Acacia-No-Ki Co., Ltd. Keywords: Acacia bark extract, Proanthocyanidins, Systolic blood pressure, Diastolic blood pressure