2.1. Study Design
RECRUITMENT
The trial was a triple-blinded, triple-crossover study with intervention periods of eight weeks duration. Between each intervention period, there was a wash-out period lasting at least three weeks. Each participant received fermented aronia extract (FAE), aronia extract (AE), or placebo in a random order. The dietary supplements were consumed twice daily, once in the morning, before breakfast and once in the evening, before dinner. The participants were randomly assigned to the treatment order using block randomization based on random sequence generation in Excel. A person not related to the study generated the codes and put them in sealed envelopes. Participants were recruited through advertisements in local newspapers, at a dedicated website for recruitment of participants (“forsoegsperson.dk”), and on social media platforms. The study candidates received study information orally and in writing and were given one week for consideration. If the candidate was interested in participating, a written consent was obtained. Participants had the right to withdraw their participation at any time.All tests and examinations were performed before and after each of the three intervention periods, e.g., a total of six repeats. Tests and examinations included fasting blood samples, oral glucose tolerance tests, and measurements of weight and waist circumference. The study was conducted at the Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark from December 2020 to April 2022. The trial was performed in accordance with the Declaration of Helsinki and approved by The Danish Ethics Committee (Journal no. 1-10-72-102-19). The trial was registered at ClinicalTrials.gov under NCT04647175.