Cumulative Urinary Excretion of Lactulose and Mannitol as Primary Outcomes in Colonic Barrier Fu

We thank Dr Camilleri1 for his interest in our paper.2 We a priori specified cumulative 8- to 24-hour urinary excretion of lactulose and mannitol as the primary outcomes to assess in vivo colonic barrier function. Although we observed a significant decrease in 8- to 24-hour mannitol excretion following the low FODMAP diet (LFD), some samples at both time points (pre- and post-LFD) demonstrated high baseline lactulose and mannitol (before administration of test sugars), as presented in Supplementary Figure 1A.