Abstract
A placebo-controlled clinical study was undertaken to evaluate the effectiveness and most effective dose of γ-aminobutyric acid (GABA)-rich Chlorella in subjects with high-normal blood pressure and mild hypertension. Sixty adult participants (47.8±10.0 years old, mean±SD) with high-normal blood pressure or mild hypertension (systolic blood pressure: 145.3±5.9 mmHg, diastolic blood pressure: 87.7±6.5mmHg) were randomly assigned to 4 groups (15 participants per group). Participants in Groups A, B, and C ingested 2, 4, and 6g of GABA-rich Chlorella per day, respectively, and participants in Group D ingested 4g of lactose (placebo), throughout the eight-week treatment period, followed by a two-week withdrawal observation period. Systolic blood pressures in Groups B and C were significantly reduced at six and eight weeks of GABA-rich Chlorella administration in comparison with the values in the placebo group (p<0.05 and p<0.01 for Groups B and C at eight weeks). There was also a tendency for a decrease of diastolic pressure, although the differences from the control group did not reach statistical significance. Two weeks after discontinuation of GABA-rich Chlorella intake, the systolic blood pressure in Groups B and C showed a rising tendency, while no change was observed in the placebo group. No adverse events were observed, and there were no marked changes in hematological, biochemical, or urinalysis parameters during the eight-week treatment period in any of the groups. These results indicate that GABA-rich Chlorella improves blood pressure in subjects with high-normal blood pressure and mild hypertension without adverse consequences in subjective symptoms or clinical signs.
