An altered permeability has been proposed to play an important role in the pathogenesis of several gastrointestinal disorders, such as irritable bowel syndrome and inflammatory bowel disease. Nutrients derived from food are able to influence the permeability of the intestine and can therefore also affect gastrointestinal symptoms. In this study, the investigators will investigate the effects of capsaicine and cinnamaldehyde, which can be found in hot peppers and cinnamon, respectively, on gastrointestinal physiology.

Objective:

To obtain more information about the effects of capsaicin and cinnamaldehyde on the intestine, these substances will be infused directly in the duodenum. Hereafter, the permeability of the intestine, gallbladder motility and the effects on satiety will be assessed.

Hypothesis:

Duodenal capsaicin and cinnamaldehyde infusion induces changes in the intestinal epithelial barrier function by selectively acting on TRPV1 and TRPA1 receptors and releasing serotonin from enterochromaffin cells as determined by the multi sugar permeability test

Inclusion Criteria:

1. Based on medical history and previous examination, no gastrointestinal complaints can be defined.
2. Age between 18 and 65 years. This study will include healthy adult subjects. Subjects over 65 years have an increased risk for comorbidities, therefore, subjects over 65 years will not be included. Furthermore, age has an influence on the homeostasis of the intestinal mucosa [21], which can potentially influence outcome parameters of the study.
3. BMI between 20 and 30 kg/m2

Exclusion Criteria:

1. History of severe cardiovascular, respiratory, urogenital, gastrointestinal/ hepatic, hematological/immunologic, HEENT (head, ears, eyes, nose, throat), dermatological/connective tissue, musculoskeletal, metabolic/nutritional, endocrine, neurological/psychiatric diseases, allergy, major surgery and/or laboratory assessments which might limit participation in or completion of the study protocol. The severity of the disease (major interference with the execution of the experiment or potential influence on the study outcomes) will be decided by the principal investigator.
2. Use of medication, including vitamin supplementation, except oral contraceptives, within 14 days prior to testing
3. Administration of investigational drugs or participation in any scientific intervention study which may interfere with this study (to be decided by the principle investigator), in the 180 days prior to the study
4. Major abdominal surgery interfering with gastrointestinal function (uncomplicated appendectomy, cholecystectomy and hysterectomy allowed, and other surgery upon judgement of the principle investigator)
5. Dieting (medically prescribed, vegetarian, diabetic, macrobiological, biological dynamic), pregnancy, lactation
6. Excessive alcohol consumption (>20 alcoholic consumptions per week)
7. Smoking
8. Blood donation within 3 months before the study period
9. Self-admitted HIV-positive state