Intestinal permeability (IP) is essential in maintaining gut-metabolic functions in health. An unequivocal evaluation of IP, as marker of intestinal barrier integrity, however, is missing in health and in several diseases. We aimed to assess IP in the whole gastrointestinal tract according to body mass index (BMI) and
liver steatosis. In 120 patients (61F:59M; mean age 45 ± SEM 1.2 years, range: 18-75), IP was distinctively studied by urine recovery of orally administered
sucrose (SO, stomach),
lactulose/
mannitol ratio (LA/MA, small intestine), and
sucralose (SA, colon). By triple quadrupole mass-spectrometry and high-performance liquid chromatography, we measured urinary recovery of saccharide probes. Subjects were stratified according to BMI as normal weight,
overweight, and
obesity, and answered questionnaires regarding dietary habits and adherence to the
Mediterranean Diet.
Liver steatosis was assessed by ultrasonography. IP at every gastrointestinal tract was similar in both sexes and decreased with age. Stomach and small intestinal permeability did not differ according to BMI. Colonic permeability increased with BMI, waist, neck, and hip circumferences and was significantly higher in obese than in lean subjects. As determined by logistic regression, the odds ratio (OR) of BMI increment was significantly higher in subjects in the highest tertile of
sucralose excretion, also after adjusting for age and consumption of junk food. The presence of
liver steatosis was associated with increased colonic permeability. Patients with lower score of adherence to
Mediterranean diet had a higher score of 'junk food'. Intestinal permeability tended to increase in subjects with a lower adherence to
Mediterranean diet. In conclusion, colonic (but not stomach and small intestinal) permeability seems to be linked to
obesity and
liver steatosis independently from dietary habits, age, and physical activity. The exact role of these last factors, however, requires specific studies focusing on intestinal permeability. Results should pave the way to both primary prevention measures and new therapeutic strategies in metabolic and
liver diseases.