2.1. Study Design, Study Participants, and Preliminary Section Criteria
COLD
In this randomized, double-blind, crossover, and placebo-controlled intervention study, 42 healthy Japanese adult volunteers (The enrolled participants were well informed about the purpose of the study, including privacy protection, health hazards and risks, compensation, data management, etc., and the procedures and contents of the study were verbally explained. Informed consent was signed by all participants prior to the preliminary checkup and screening for inclusion and exclusion criteria. Enrolled subjects were asked to complete a preliminary health screening form, and to be eligible, the following criteria had to be met: (i) 20 years of age or older and computer literate; (ii) body mass index (BMI) < 30 kg/mA questionnaire comprising dietary food intake, quality of life, medical conditions, bowel habits, general lifestyle, sleep conditions, health supplement uses, and an allergic statement was distributed to participants who expressed interest and enrolled in this study two weeks before the start of the screening process. Subjects were evaluated for cold sensation conditions using Terasawa’s diagnostic criteria, as reported elsewhere [