2. Materials and Methods
The study protocol was approved by the Ethical Committee of the Faculty of Medicine of the Technical University of Munich (approval no. 201/17S). All procedures used were in agreement with the Declaration of Helsinki of 1975, as revised in 2013. Written informed consent was obtained from all participants before starting the study procedures. Detailed information about study participants, intervention, and design of the Freising Fiber Acceptance Study has been previously reported [Quality of life was assessed using the validated questionnaire EUROHIS-QOL 8 [Data analysis was performed in R version 4.2.1. Results are represented as mean ± SD. 