Regular Intake of Japanese Traditional Rice Fermented Beverage, Koji Amazake for 4 weeks Decreases Systolic Blood Pressure A Randomized, Double-blind,Placebo-controlled, Parallel-group Comparative Study

Background Japanese traditional beverage koji amazake is made by ihe fermentation of rice by filamentous fungi. Aspergillus oryzae, koji. Though the history of the fermented beverage is long in Japanese culture and its health-promoting effects have been widely believed, there have been only a few researches showing the effects to human health. Methods We performed a randomized, double-blind, placebo-controlled parallel group comÂparative study to evaluate the health-promoting effects of the fermented beverage. We also investigated the chemical components and their activities from the amazake extracts. Results Twenty participants were allocated into two groups of 10 subjects. Each subject took either 160 g koji amazake or placebo in a day for 4 weeks. We found significant decrease in sysÂtolic blood pressure after the regular intake of ama2ake, while we did not find any changes in the diastolic blood pressure arid pulse. The water and ethanol extracts from the beverage used in the clinical study have an ACE inhibition activity. Comparing their inhibition rates with that of Valyl-iyrosine. a dipeptide which is known to have an ACE inhibition activity, we estimated that drinking of 80 mL amazake in a day is enough to obtain the clinical effect of decrease in systolic blood pressure The koji amazake also contains much glucose and various amino acids, which provide energy for our activities. Conclusion These results suggest that daily intake of koji amazake has great possibilities to improve our health-related quality of life (QOL), and that Japanese traditional diet is worth reevaluated for the health promotion. (Jpn Pharmacol Thcr 2020 : 48 : 305-12).