2.1. Research Ethics and Participants
The present study adhered to the principles of the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research Involving Human Subjects. Documents such as the study protocol, the investigator’s brochure, the explanation form, and the consent form were submitted to the ethics committee of the Faculty of Health and Sports Science, Juntendo University, and the study was conducted following approval by the committee (approval number: 29–13). This study was registered at the University Hospital Medical Information Network Clinical Trial Registry as UMIN000028717.The study design was a randomized, placebo-controlled, double-blinded, parallel-group trial for healthy Japanese student volunteers. In August 2017, we recruited students from Juntendo University, who were aged 18 years or older, who belonged to the long-distance track and field team, and who regularly exercised at least four times a week, by posting a notice at the Faculty of Health and Sports Science, Juntendo University. The experiment was conducted from late August to September 2017.The minimum sample size was estimated on the basis of CD86 expression, which is one of the activation markers of pDCs. Our previous study reported that the standard deviation for CD86 was 20%, and the difference between the pre- and post- ingestion mean value was 15% [