Intestinal permeability in different feedings in infancy.
AIM: To determine the intestinal permeability (IP) as a marker of intestinal epithelial integrity in formula-fed infants compared with healthy breast-fed infants. METHODS: IP was measured in 57 healthy infants less than 4 months old. A dual sugar test with lactulose and mannitol was performed. Three urinary ratios were established: lactulose/mannitol (L/M), lactulose/creatinine (L/C) and mannitol/creatinine (M/C). Five groups were studied: breast-fed (n = 11), prebiotic supplemented formula (n 17), nucleotides supplemented formula (n = 9), LC-PUFA supplemented formula (n = 9) and LC-PUFA and nucleotides supplemented formula (n = 11). RESULTS: We have not found any difference in IP between breast-fed and formula-fed infants nor when the different formulas are compared with each other. The indirect information of the paracellular pathway by the ratio L/C and the transcellular route by the ratio M/C reflects some difference when the ingredients added are fructooligosaccharides and galactooligosaccharides, expressing a higher degree of lactulose permeation with respect to mannitol. When LC-PUFA supplementation was evaluated a lesser ratio of L/C was found, expressing intestinal barrier related to a process of epithelial tight. CONCLUSIONS: The most important factor in the maintenance of the integrity of epithelial barrier function is probably the delivery of nutrients in the gastrointestinal tract. The role of the different ingredients added should be clarified.