infants critically ill patients and the elderly furthermore the nutritional composition may be used as a complete or a supplemental nutrition for preventing or treating bacterial overgrowth in the intestine bacterial translocation septicemia and reduced availability of nutrients in preterm or term newborns infants critically ill patients and the elderly without wishing to be bound by theory it is postulated that the beneficial effect of the protein hydrolyzate with respect to bacterial overgrowth is thougth to be linked to the high digestibility and rapid absorbtion of the protein hydrolysate the fact that most of the proteinaceous material is present in small fractions for example di tri or tetrapeptides has the consequence that these are completely absorbed in the small intestine even in patients with impaired gastrointestinal function would such patients or a preterm baby consume intact protein this protein would not be entirely absorbed in the small intestine and would reach the lower end of the ileum there the proteinaceous material may serve as a substrate for bacteria that usually do not colonise this area of the digestive tract in healthy individuals it is therefore found that bacterial overgrowth may be prevented and cured by increasing the digestibility of the proteinaceous material more specifically by providing a protein hydrolyzate rather than intact protein to the affected individual again it is not proved that this explanatory model accounts totally for the surprising effects reported herein the following example is given by way of illustration.