Hypertension Research in press Miso (Japanese soybean paste) was protective against hypertension compared to same amount of sodium chloride diet in Dahl salt-sensitive rats

The purpose of this study was to compare the effects of Miso and sodium chloride (NaCl) on blood pressure in both sexes Dahl and SD rats. The systolic and diastolic blood pressures were measured at 2, 4, 8 and 12 weeks of treatment with a Miso diet including 2.3%NaCl or diets with 2.3% and 1.9% NaCl or normal diet (MF diet, Oriental Yeast Co) with 0.3% NaCl diet. The rats were autopsied after 12 weeks on a diet. Diastolic blood pressure in male Dahl rats was significantly increased by the 2.3% NaCl diet as compared with the MF group (P<0.01) or Miso group (P<0.05) from 4 weeks of treatment. After that diastolic and systolic blood pressures in both high NaCl groups were significantly increased when compared with the MF or Miso group. Systolic blood pressure in female Dahl rats on 2.3% NaCl was significantly increased from 8 weeks after treatment. Nephropathy was observed in both sexes of Dahl rats but not SD rats. These results show that blood pressure is not increased by the Miso diet.