Inclusion Criteria:  Age ≥60 ≤90 years, weight ≥50 kg, generally healthy  Signed informed consent form Willingness to follow the prescribed diet for the duration of the study No participation in any other clinical trial (current or within the last 30 days)  Exclusion Criteria:  Taking intestinal therapeutics, antibiotics, immunosuppressants or similar. (if necessary, decision on a case-by-case basis) Pregnancy/breastfeeding Relevant violations of the dietary protocol Occurrence of relevant diseases (if necessary, individual case decision) Withdrawal of consent Placement in a clinic or similar facility due to official or court order