2.1. Experimental Design and Procedures
This was a four week, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov NCT04823533). The final experimental design is shown in Prior to the beginning of the experiment, all participants received a bag of materials. Each bag contained detailed protocol instructions, materials required for the three measurements of stool sampling and storage, and the probiotic or placebo sticks for the full experiment. Participants filled out the questionnaires and collected the stool sample on the 3 study timepoints, at days 1, 28, and 84. Following a very strict protocol of hygienic sample collection, participants stored samples at −20 °C in the freezer section of their home refrigerator until they were picked up by the researcher the same day. In the present report, no additional information regarding the stool sampling and processing will be delivered, given that no reference to this data nor results will be done.This study obtained approval of the Bioethics Committee of the Faculty of Medicine at the Pontificia Universidad Católica de Chile. Written informed consent was obtained from all participants before the study. Reporting of findings was done in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines [