We evaluated intestinal permeability in children with food allergy by the measurement of lactulose/L-rhamnose urinary excretion ratio (L/R ratio) after orally loaded lactulose (a disaccharide) and L-rhamnose (a monosaccharide).
The mean L/R ratio in food-allergic patients restricted major offending foods (eggs and cow's milk) partially was significantly higher than in those restricted major offending foods strictly (p<0.01). Furthermore, the mean L/R ratio in patients restricted major offending foods strictly was comparable with that in healthy subjects (controls). Individual changes in intestinal permeability were also evaluated after elimination diets and after oral food challenges. The mean L/R ratio decreased significantly after elimination diets (p<0.05) and increased significantly after the positive food challenges (p<0.05) in patients with food allergy.
In non-atopic children suffering from respiratory infections during the previous 10 days, the mean L/R ratio was significantly higher than that in controls (p<0.05).
In conclusion, the measurement of lactulose/L-rhamnose excretion ratio was useful to evaluate alterations in the mucosal barrier function under elimination diet and food antigens intake.