The effect of gluten on intestinal fermentation, gastric and gallbladder emptying in healthy volunteers

Background: The relationship between gluten ingestion and gastrointestinal tract function is a matter of debate. Aim: We analysed the effect of gluten on gastric and gallbladder emptying and intestinal fermentation in healthy volunteers. Methods: Ultrasound measurement of gastric and gallbladder emptying after both gluten-containing and gluten-free meals was performed in 18 volunteers (8 women, age 25.0 ± 2.5 years; BMI 22 ± 1.9). Breath hydrogen excretion after a gluten-containing meal, a gluten-free meal and a gluten-free meal with added gluten powder was measured in 16 volunteers (10 women, age 25.2 ± 2.7 years; BMI 22 ± 1.8). The severity of symptoms was monitored. Results: Gluten presence in the meals was not recognised. Gastric emptying time was 81.6 ± 13.8. min after gluten-containing and 73.9 ± 21.6. min after gluten-free meals (p = 0.11). Percentage ejection fraction after gluten-containing meals was 60 ± 9% and 60.6 ± 6% after gluten-free meals (p = 0.68). Peak and cumulative hydrogen excretion were significantly higher after gluten-containing than after gluten-free meals (peak: 12.5 ± 7.3 vs 6.5 ± 5.1 parts-per-million, p <0.01; and cumulative: 2319 ± 1720 vs 989 ± 680 parts-per-million/minute, respectively; p <0.01). Adding gluten powder to the gluten-free meal did not modify fermentation. Symptoms were mild and not different after the meals. Conclusions: In healthy volunteers, gluten may induce gastrointestinal alterations. Further studies are needed to clarify which patients could benefit from dietary modification.