First Online: 15 August 2019
Compliance with Ethical Standards
: KY is an employee of Riken Vitamin Co., Ltd. RM has no conflicts of interest to declare.
: The study participants gave written informed consent prior to their inclusion in the study. The study was approved by the Oriental Ueno Detection Center Ethics Committee (approval No. 2017–37) and study protocol was registered with University Hospital Medical Information Network Clinical Trials Registry (UMIN000031050). This study was conducted in accordance with the principles of the Declaration of Helsinki and the national Ethical Guidelines for Medical and Health Research Involving Human Subjects, as applicable in Japan.