The purpose of this study is to determine the optimal dose of soluble fibers that induces tolerable gastrointestinal symptoms.

Inclusion Criteria:

1. 18-60 years of age inclusive, and Body Mass Index (BMI) 18.5-29.9 kg/m2 inclusive; who according to the Rome IV fulfil criteria for self-perceived sensitivity to oligosaccharide FODMAP A and B including participants diagnosed with IBS, FBFB, or FBD-U.

2. 18-60 years of age inclusive, and BMI 18.5-29.9 kg/m2 inclusive; who fulfil criteria for self-perceived sensitivity to oligosaccharide FODMAP A and B, not diagnosed with IBS, FB or FBD-U as per Rome IV Criteria but reporting abdominal pain at least once a week AND/OR bloating/distention at least once a week as per ROME IV diagnostic questionnaire.

3. Individuals who fully understand the objectives of the study, who are willing to provide consent and agree to follow the protocol of the study.

4. Participant is covered by French health insurance.

5. Participant agrees to be registered in the national database of participants participating in clinical research.

6. Participant is willing and able to complete the electronic Patient Reported Outcomes (ePRO) using a digital device (e.g. smartphone with minimal OS version of IOS 16.6 or android 11 or more recent) having access to internet (web site).

7. Female participants must either be postmenopausal for at least 12 months or have undergone specific surgical procedures resulting in sterility (such as hysterectomy, bilateral oophorectomy, or bilateral tubal ligation) or they are using one of the medically approved contraceptive methods listed below from V1 until the end of the study, such as, but not exclusively:

   • oral contraception
   • intra-uterine device (IUD)
   • double barrier method (e.g., condoms and spermicide)
   • abstinence, when the opinion of the investigator, their occupation or lifestyle gives efficient evidence that abstinence will be maintained throughout the study and for one month thereafter.

Exclusion Criteria:

1. Individuals who score below 75 or who score 300 or above on the Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) if diagnosed with IBS using the Rome IV criteria.
2. Individuals that are diagnosed with any other chronic gastrointestinal or metabolic disease or condition including inflammatory bowel disease, coeliac disease, fistulas or physiological/mechanical gastrointestinal obstruction, diverticulitis, gastric bezoar, radiation enteritis, suspected or known strictures.
3. Change of dietary habits within the 4 weeks preceding V1 (e.g., start of a diet rich in fibers) or planned change (e.g., start of a new diet during study participation).
4. Individuals with specific and extreme diets (e.g.: strict low-FODMAP, gluten free, high fiber diet, etc.).
5. Individuals who anticipate changes to consumption of naturally probiotic/prebiotic containing foods e.g., yogurt with live cultures etc., in the next 2 months.
6. Participant who has planned to participate in another clinical study during the period of this study OR participant involved in any other clinical study in the past four weeks.
7. Participant with known allergy to any component of the study product(s).
8. Individuals receiving any form of treatment likely to interfere with metabolism or dietary habits (e.g., anorexia, weight loss.).
9. Participant with any intake of antibiotics or intestinal antiseptics in the previous month (within 30 days) prior to screening visit (V1).
10. Individuals with current use of medication with potential central nervous system effects as judged by the investigator.
11. Individuals with previous digestive surgery (except for appendectomy performed more than 2 years ago).
12. Participants performing strenuous daily exercise for more than 1.5 hours at a time (e.g., intensive daily cardio for more than 1.5 hours).
13. Oral disease or medical condition that may impact on hydrogen and methane breath sampling (e.g., gingivitis, halitosis, oral thrush, candidiasis, asthma).
14. Participant with any intake of drugs that might modify gastrointestinal function (e.g., regular use of laxatives, anti-diarrheal agents, anti-emetics, prokinetics, proton pump inhibitors (PPIs), NSAIDs, antacids, etc.) or breath function (e.g. aerosol) in the past 8 weeks or, plan to use.
15. Individuals who take supplements used to treat bloating: activated charcoal, enzymes (ex: lactase, alpha galactosidase, fructanase).
16. Women who report they are pregnant/lactating/planning pregnancy.
17. Recent/ongoing consumption of probiotics/prebiotic/synbiotics supplements (past 28 days).
18. Participant is a smoker (usual use of any tobacco products, nicotine, nicotinecontaining products or all types of e-cigarette in the previous 3 months).
19. Alcohol consumption that exceeds the recommended amounts (>10 standard glasses per week or > 2 standard glasses per day).
20. Participant living in the same home as a participant currently participating in this study.
21. Participants defined as individuals whose willingness to volunteer in the clinical trial may be unduly influenced by the expectation, whether justified or not, of benefits associated with participation, or of a retaliatory response from senior members of a hierarchy in case of refusal to participate. (Examples are members of a group with a hierarchical structure linked to the Investigator or to the Sponsor, such as students, subordinate hospital and laboratory personnel, employees of the Investigator or of the Sponsor, relatives of the Sponsor).
22. Employees and/or children/family members or relatives of employees of Danone Global Research & Innovation Center or the investigational sites.
23. Belonging to a population covered by articles L.1121-6 (persons deprived of their liberty by judicial or administrative decision, persons under psychiatric care), and L.1121.8 (adults under legal protection or unable to express their consent) of the CSP (French Public Health Code).
24. Participant admitted to a health or social care facility
25. Individuals with a known case of diabetes mellitus (type 1 or type 2), or those with a known HbA1c ≥ 6.5% at screening, or currently receiving antidiabetic treatment (oral or injectable).
26. Having received, during the last 12 months, indemnities for participation into clinical studies exceeding the annual threshold of 6000€ (including participation to this study).
27. Individual whom are not able to follow Protocol instructions and restrictions (i.e. night workers).

Secondary exclusion criteria:

Exclusion criteria at the end of the "placebo challenge" (Visit 2):

1. Participant "nocebo responder", defined as a participant who reports "Worse" at the question related to overall digestive symptom ("How do you consider in the past 7 days, your GI well-being (intestinal transit, stool frequency and consistency, abdominal pain/discomfort, bloating, flatulence/passage of gas, borborygmi/rumbling stomach) compared to the period before beginning the consumption of the study product?)