Table 1 List of inclusion and exclusion criteria for participation in the study

• Healthy volunteers without clinical diagnosed diseases with relevant impact on GI system or on visceral motility

• GI symptoms of at least 5-points for the previous 3 months based on self-assessment using a 5-point scale questionnaire ^a, or

• Reduced bowel movements defined as an average of >1 and ≤ 5 stools per week for the previous 3 months based on self-assessment

• Age ≥ 18 and ≤ 70 years

• Male or female

• No pregnancy in the 6 months prior to study

• BMI: 18–35 kg/m²

• Stable body weight (± 5%) for at least 6 months

• No weight reduction treatment during study period

• Written consent to participate in the study

• Able and willing to follow the study protocol

• History of severe GI/hepatic, hematological/immunologic, metabolic/nutritional disorders, endocrine disorders, celiac disease, type I diabetes mellitus, major surgery and/or laboratory assessments which might limit participation in or completion of study period

• Use of medication, including vitamin supplementation, except oral contraceptives, within 14 days prior to first dosing. Some medication may be used, if it is considered not to influence GI function and motility

• The use of any non-steroidal inflammatory drugs (NSAIDs) starting 14 days prior to first dosing is prohibited

• Systemic antibiotics treatment within 60 days prior to first dosing

• Intake of laxatives or anti-diarrheic drugs within 14 days prior to first dosing

• Change of dietary habits within the 4 weeks prior to screening

• Participants anticipating a change in lifestyle or physical activity levels during the study

• Major abdominal surgery interfering with GI function

• Known pregnancy or lactation

• Dependence on illegal drugs or alcohol

• Smoking within the last 3 months

• Prohibited use of pro-, pre- or synbiotics from 30 days before first dosing and during the study period

• Hepatitis C-, B- or HIV-positive

• History of any major side effects towards intake of pro- or prebiotic supplements of any kind

Additional inclusion criterion

NA

• At the end of the run-in phase a score of ≥ 5-points for GI symptoms must be obtained at least for 50 subjects, based on the average calculated for the daily scores of the 2-week run-in period ^a

NA