The impact of milk and weaning diet on gastrointestinal permeability in English and Gambian infants.

To test the hypothesis that cow's milk formula and weaning diet may damage the gut mucosa, the gastrointestinal permeability of 77 healthy English and Gambian infants was measured from the urinary recovery of the markers lactulose and mannitol included in feeds. All infants were born at term and studied at 6, 12 and 18 weeks of age. No infant developed diarrhoea or failed to thrive. Infants fed on cow's milk formula had higher urinary lactulose: mannitol excretion ratios than breast-fed infants at 6 weeks of life (P less than 0.05). There was no significant difference in the urinary marker excretion ratios of English formula-fed and Gambian breast-fed infants at 12 weeks. An increase in urinary lactulose: mannitol excretion ratios was seen in all infants at 18 weeks. This was more probably due to increasing age than to the introduction of weaning diet. Cow's milk formula feeding was associated with greater intestinal permeability than breast feeding in infants aged 6 weeks. The introduction of weaning diet after 6 weeks did not appear to have an impact on the gastrointestinal permeability of healthy growing infants born in either England or rural Gambia.