Carbohydrate-induced Resilience of the Gut Microbiome After Antibiotics Use

In this double-blind, randomized placebo-controlled study, 40 overweight, but otherwise healthy adults will first receive vancomycin for 7 days (3x 500mg per day) to disturb the gut microbiome. They will then receive either indigestible fiber supplementation (classified) ór a placebo for the following 8 weeks. All study parameters will be assessed in two parallel groups, to which subjects will be assigned using minimization. After initial screening, participants will be asked to visit the university for a total of 6 times during a period of 11 weeks. A clinical investigation day will take place at baseline, after antibiotics use and after the supplementation period. The remaining 3 visits will be short visits during the supplementation period (week 2, 4 \& 6 of supplementation). Participants will be asked to collect feces every day before the university visits. During the clinical investigation days, an abdominal subcutaneous adipose tissue will be taken under fasting conditions. Participants will also perform a 7-point oral glucose tolerance test to assess their insulin sensitivity. Furthermore, blood samples will be taken in the fasted state to assess markers of fat metabolism, short-chain fatty acids, gut hormones and inflammatory markers. Participants will be asked to hand in collected feces and to fill in questionnaires regarding stool consistency, stool frequency and physical activity. Lastly, they will be asked to hand in filled-in 3-day food diaries. On the 3 remaining visits during the supplementation period, participants will hand in collected feces and food diaries, and fill in the questionnaires. For these 6 visits, participants will have to invest approximately 14 hours.