In the present randomised double blind controlled study, we will study the effects of a oligosaccharides vs a placebo on the change in stool consistency and stool frequency in children with hard or lumpy stools.

Firm, hard or lumpy stools can be problematic for young children and might come as a precursor of functional constipation in childhood. The cause of harder stools in childhood is incompletely understood. But it is likely that harder stools in childhood are linked to among others withholding behaviour of stools and a low fibre intake. As hard stools may precede functional constipation, the aim of the study is to investigate the effect of a prebiotic fiber versus a placebo on defecation parameters in healthy children with hard or lumpy stools. We hypothesize that consumption of a prebiotic fiber results in softer stools.

Inclusion Criteria:

• Written informed consent
• aged 1-4 years
• Hard and/or firm stools as scored by a stool questionnaire

Exclusion Criteria:

• Children that meet the Rome IV criteria for functional constipation
• Children who suffer from any other GI complaints, known structural GI abnormalities, or previous GI surgery
• Any condition that would make it unsafe for the child to participate.
• Children with clinically significant cardiac, vascular, liver, pulmonary, psychiatric disorders, severe renal insufficiency, human immunodeficiency virus, acquired immunodeficiency syndrome, hepatitis B or C or known abnormalities of haematology, urinalysis, or blood biochemistry, as checked by the inclusion questionnaire.
• Children who are allergic to cow's milk or fish
• Use of antibiotics or other medicines or food supplements, and breast milkfeeding, which can influence defecation and gut microbiota 4 weeks prior to the study
• Children that participate in another clinical trial