Enteral intake of non-metabolic monosacharide and disaccharide, followed by measurement of the urinary excretion ratio of the two, is a method used to investigate intestinal permeability. L/R ratio (lactulose/1-rhamnose urinary excretion ratio) is considered an indicator of permeability of the small intestine. An increased L/R ratio is caused by mucosal disorders of the small intestine.
The L/R ratio in all patients (n=92) with Crohn's disease was 0.079±0.081 (mean±S.D.), which was significantly higher than the value in normal controls (0.027±0.009, n=20, p<0.05). In 39 patients with Crohn's disease, we assessed intestinal permeability before after treatment with an elemental diet, and during remission.
The L/R ratio was 0.120±0.092, before treatment and 0.065±0.097 after treatment (p<0.05), showing increased intestinal permeability before elemental dietary treatment. During remission, the L/R ratio was 0.035±0.028;this did not differ significantly from the value obtained after treatment.
We conclude that intestinal permeability is useful for investigating disease activity in patients with Crohn's disease.
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