Processed soymilk effectively ameliorates blood pressure elevation in spontaneously hypertensive rats

Processed soymilk (PSM) was produced from original soymilk by treatment with a commercially available proteinase to generate inhibitory peptides against the angiotensin I-converting enzyme (ACE). Furthermore, we investigated PSM's potential hypotensive effect on spontaneously hypertensive rats (SHR). Processed soymilk at doses of 0.167 and 0.583 ml/kg body weight after a single oral administration significantly decreased systolic blood pressure in SHR compared to control (non-processed soymilk). Repeated administration (3 weeks) of PSM at the same doses significantly reduced blood pressure elevation in SHR compared to control. After repeated PSM administration, its inhibitory activity against serum ACE was significantly higher compared to the control. Serum levels of the angiotensin II after PSM administration was significantly lower than control. Serum lipid profiles were similar between control and experimental (PSM) SHR. Thus, PSM ingestion may lower high blood pressure and ameliorate cardiovascular diseases related to hypertension without causing adverse side effects.