The goal of this crossover study is to evaluate the systemic availability of short-chain fatty acids (SCFA) that are either administered in the small intestine or the colon in healthy volunteers. The main question it aims to answer is whether the site of administration affects the amount of SCFA that reaches the systemic circulation. On two test days participants will ingest capsules filled with SCFA that are specifically delivered in the small intestine or the colon. After ingestion, blood samples will be collected at regular time points.

Inclusion Criteria:

• female and male
• healthy participants
• age within 18 - 50 years
• normal BMI (18.5-25 kg/m^2)

Exclusion Criteria:

• Chronic gastrointestinal disorders such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), celiac disease, chronic constipation (less than 3 stools a week) and chronic frequent diarrhoea (more than 3 stools a day)
• Previous abdominal surgery, except from appendectomy
• Being on a weight loss, gluten-free, lactose-free, or vegan diet
• The donation of blood during the last 3 months or suffering from low blood haemoglobin levels
• The use of antibiotics or other medication that affects the gastrointestinal tract 3 months preceding the study and/or during the study
• The use of prebiotics or probiotics 2 weeks preceding the study and/or during the study
• Pregnancy, lactation or wish to become pregnant during the study period
• Previous or current substance/alcohol dependence or abuse (> 2 units per day/14 units per week)

No IPD data will be shared with other researchers.