Blood-pressure-lowering effect of a novel fermented milk containing γ-aminobutyric acid (GABA) in mild hypertensives

Objective: To study the effect of a new fermented milk product containing GABA (FMG) on the blood pressure (BP) of patients with mild hypertension. Design: A randomized, placebo-controlled, single-blind trial. Setting: The study was carried out at the outpatient clinic of the Cardiovascular Disease Center, Tokyo Metropolitan Police Hospital, Japan. Subjects: The study population comprised 39 mildly hypertensive patients (16 women and 23 men) aged 28–81 y (mean, 54.2 y). Interventions: The study consisted of a 12-week period of daily intake of FMG or placebo (weeks 1–12) followed by 2 weeks of no intake (weeks 13 and 14). We measured the peripheral BP and heart rate of seated patients at weeks 0, 2, 4, 8, 12 and 14. Routine blood study and urinalysis were performed before and after the intake. Results: There was a significant decrease of BP within 2 or 4 weeks, and it remained decreased throughout the 12-week intake period. For the FMG recipients, the mean decrease after 12 weeks was 17.4±4.3 mmHg in the systolic BP (SBP) and 7.2±5.7 mmHg in the diastolic BP (DBP). Both of these values differed statistically from baseline levels (P<0.01), and the SBP of the FMG group differed from the placebo group (P<0.05). Heart rate, body weight, hematological and blood chemistry variables, and urinalysis results (glucosuria and proteinuria) did not vary both groups throughout the study. Conclusions: FMG may contribute to lowering BP in mildly hypertensive people.