Objectives: "IZUMI" is a new kind of vinegar resulting from an improvement in the manufacturing method of Kurosu, a traditional vinegar product made from unpolished rice. We evaluated the antioxidant activity of this new Kurosu by means of measuring the level of diacron-reactive oxygen metabolites (d-ROM), the biological antioxidant potential (BAP), as well as RBC deformability using the microchannel array flow method.
Participants: Ten healthy, untrained female volunteers participated in this study.
Measurements: All subjects drank 50 ml of "IZUMI" on a daily basis, and blood samples were collected pre-"IZUMI" (I), after one month "IZUMI" consumption (II), and after two months "IZUMI" consumption (III). The subjects continuously wore a lifecorder during a 7-day period and the nutritional intake was measured before the initial blood sample collection.
Results: There were no significant changes in weight, BMI, fat mass, or fat-free mass. There were no significant differences in daily energy consumption, physical activity and nutritional intake. Peripheral blood variables did not change significantly. The drinking of " IZUMI " increased serum BAP level gradually, and after 30 days it was significantly higher as compared to the pre-drinking level. The serum level of d-ROM and blood filtration time (BFT) decreased by drinking "IZUMI"; with d-ROM significantly lower than the pre-drinking level after 30 days and BFT significantly decreased after 60 days (all P < 0.05).
Conclusions: These results suggest that "IZUMI", a Kurosu containing a higher level of amino acids, increases antioxidant activity and reduces oxidative stress and blood filtration time in female subjects.