The anti-hypertensive effect of processed rice bran (PRB) was recently reported, for which the novel peptide Leu-Arg-Ala (LRA) was identified as the functional substance. The purpose of this study was to assess the anti-hypertensive effects of a rice bran supplement containing PRB in individuals with high-normal blood pressure (systolic blood pressure (SBP): 130⁻139 mmHg and/or diastolic blood pressure (DBP): 85⁻89 mmHg) or grade 1 hypertension (SBP: 140⁻159 mmHg and/or DBP: 90⁻99 mmHg). One hundred individuals with high-normal blood pressure or grade 1 hypertension were recruited to participate in this double-blind, randomized, placebo-controlled study. Participants were randomly allocated to the placebo group (n = 50) or the test group (n = 50). Each group took four test tablets (43 μg LRA/day) or four placebo tablets daily. The decrease in blood pressure in the test group compared with the placebo group was the primary outcome. Adverse events were recorded and hematological/urinary parameters measured to determine the safety of the supplement, which was the secondary outcome. In total, 87 participants completed the study. The SBP of the test group at 12 weeks was significantly lower than that of the placebo group (p = 0.0497). No serious adverse events were observed. Daily consumption of a rice bran supplement containing PRB can safely improve mildly elevated blood pressure.
Keywords: anti-hypertensive effect; double-blind randomized placebo-controlled study; high-normal blood pressure; novel peptide; rice bran.