2.6. Randomization and Blinding
The allocation supervisor (Statcom Co., Ltd., Tokyo, Japan), who had no direct involvement in the study, organized five teams of participants based on their menstrual cycle timing to ensure that the intervention was timed to fit each participant’s menstrual cycle. They were then randomly assigned into two groups using a computer-generated random sequence for each team. It was also confirmed that there were no differences in the participants’ age and the MDQ total score during the premenstrual and menstrual periods of menstrual cycle −1 between the assigned groups. This study was conducted in a double-blind manner, with test foods and measurement data concealed from both the research investigators and the participants throughout the study.