Development of Intestinal Permeability Tests for Clinical Nutrition and Metabolic Health Studies

Crossover clinical trial on 10 subjects (5 women, 5 men) with 3 intestinal permeability tests (3-day washout) as follows: 1) fasting; 2) meal-provoked; and 3) meal-provoked with acute aspirin challenge to assess the test's feasibility and capacity to detect alterations in intestinal permeability after aspirin-induced intestinal barrier defects.

Each test will be performed after a 12h fast. Subjects will provide fasting blood and urine samples, fully empty their bladders and drink 50mL of water with/without soluble aspirin (650mg). After 30 min., subjects will drink 500mL of water or mixed meal beverage (22g protein, 26g fat, 52g carbs) with mannitol (2g) and lactulose (4g). A standardized snack and water (200mL) will be provided at 3h. Blood samples will be taken at 2h, 3h and 4h. All urine will be collected over 5 hours. Collection times were adapted to account for potential delays in gastric emptying (mixed meal vs. water). Lactulose-to-mannitol ratios, by HPAEC-PAD method, in urine and blood will be compared by phases using mixed linear models.