Aging gut study: do older adults digest protein differently?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Aged 18-35 years or 67+ years * Body mass index (BMI) between 18.5 and 30 kg/m2 * Regular stool frequency ranging from 1-3 times/day Exclusion Criteria: * History of cardiovascular, respiratory, gastrointestinal, urogenital, neurological, psychiatric, dermatologic, musculoskeletal, metabolic, endocrine, haematological, immunologic disorders, allergy, major surgery and/or laboratory assessments which might limit participation in or completion of the study protocol, interfere with the execution of the experiment, or potential influence the study outcomes (to be decided by the principal investigator and responsible physician) * Major abdominal surgery interfering with gastrointestinal function (upon judgement of the principal investigator and responsible physician) * Use of medication which limit participation in or completion of the study protocol, interferes with the execution of the experiment, or potential influences the study outcomes (to be decided by the principal investigator and responsible physician) * Use of supplementation (i.e. protein, vitamin, pre- and probiotic supplementation) within 14 days prior to testing * Administration of investigational drugs or participation in any scientific intervention study prior or during the study, which may interfere with this study (upon judgement of the principal investigator and responsible physician) Specific diet (e.g. vegetarian, vegan, gluten free, no diary) within the study period * Planning to lose weight during the study period * Excessive alcohol consumption (defined as \> 14 alcoholic consumptions per week) * Smoking * Drug use * Pregnancy * Lactation * Donated blood three months prior to the test day * No given permission to register participation in electronic patient file at MUMC+ and to add records of gastroduodenoscopy