Intestinal permeability changes during the first month: effect of natural versus artificial feeding

The aim of the study was to investigate the effect of age and feeding pattern on intestinal permeability during the first month of life. The subjects were 72 full-term, healthy neonates who were (a) exclusively breast-fed (BF group, n = 36) or (b) artificially fed (CM group, n = 36) with either an adapted formula (AF group, n = 17) or a partly hydrolyzed (hypoantigenic) formula (HA group, n = 19). A lactulose/mannitol (lac/man) intestinal permeability test was performed at 1 and 7 days (steady-state method, n = 72), then at 30 days of life (single oral load, n = 47). Urinary lactulose and mannitol were measured by HPLC. The mean lac/man urinary ratio dropped from 1.27 +/- 0.73 (day 1) to 0.34 +/- 0.36 at day 7 and to 0.22 +/- 0.21 at day 30. At 7 days BF infants showed a significantly lower lac/man urinary ratio (0.22 +/- 0.25) than the CM group (0.47 +/- 0.41). The human neonate shows a developmental pattern of sugar intestinal permeability that resembles gut closure observed in other mammals. Intestinal permeability decreases faster in breast-fed babies than in those fed with adapted or HA formulas.