Effect of aspirin dose on gastrointestinal permeability.

The primary purpose of this study was to determine the aspirin dose that increases gastrointestinal (GI) permeability. A pilot study was also conducted to determine whether the menstrual cycle affects GI permeability. Both portions of the study involved 4 experimental conditions. For the aspirin portion, 8 subjects ingested 0 mg, 325 mg, 650 mg, or 975 mg of aspirin the night before and the morning of an experiment. For the menstrual cycle pilot study, 5 female subjects with regular menstrual cycles were tested for GI permeability on the same day each week for 4 weeks. GI permeability was assessed by the urinary excretion of ingested probes. Sucrose (5 g) was used to determine gastroduodenal permeability. Lactulose (5 g) and rhamnose (2 g) were used to assess small intestinal permeability via the lactulose-to-rhamnose urinary excretion ratio (L/R). The data indicated that the menstrual cycle had no effect on GI permeability. In contrast, gastroduodenal permeability was significantly (P <0.008) increased following a dose of 650 mg aspirin and small intestinal permeability (L/R) was significantly (P <0.008) increased following a dose of 975 mg aspirin. These results suggest healthy individuals should be cautious even with acute aspirin use as it may result in GI barrier dysfunction.