A team from Barcelona, Spain, investigated whether lipids induce intestinal gas retention in irritable bowel syndrome (IBS).
Lipids are known to generate various motor and sensory effects on the gut, and modulate intestinal gas dynamics.
Alteration of this regulatory mechanism may result in impaired gas transit in IBS patients.
A total of 30 patients with IBS and 45 healthy subjects were included in the study.
Evacuation of gas infused into the jejunum (at 12 ml/min) was measured for 2 hours in each individual.
The effect of simultaneous duodenal perfusion of lipids at 0 kcal/min (saline), 0.5 kcal/min, and 1 kcal/min was tested in groups of 15 subjects each.
In healthy individuals, duodenal lipids at 1 kcal/min, but not at 0 kcal/min or 0.5 kcal/min, produced significant gas retention (281 ml vs 22 ml at 0 kcal/min and -65 at 0.5 kcal/min).
Patients with IBS exhibited gas retention during saline perfusion (259 ml at 0 kcal/min vs healthy subjects). They were also hypersensitive to duodenal lipids (505 ml retention at 0.5 kcal/min vs saline and vs healthy subjects).
| Lipids inhibit intestinal gas transit in IBS patients.
| Gastroenterology |
The researchers found that the ‘gas plus lipids' challenge test discriminated patients with 100% sensitivity and 93% specificity.
Jordi Serra, of the Vall d'Hebron General Hospital, Barcelona, concluded on behalf of fellow authors, "Physiologic concentrations of intestinal lipids exert an inhibitory control on intestinal gas transit, and this mechanism is up-regulated in patients with IBS."
"Hence, impaired gas propulsion, shown by the gas challenge test, may be useful as a diagnostic test if replicated in a larger series of patients."
In an accompanying Editorial, Michael Camilleri and Silvia Delgado-Aros, of the Mayo Foundation, Rochester, Minnesota, USA, comment, "The authors propose the ‘gas-lipid challenge test' to positively diagnose IBS, based on the good discrimination between health and IBS patients with bloating.
"However, no data are provided regarding gas transit in patients with bloating and organic gastrointestinal diseases.
"Hence, the real validity of this test to differentiate functional from organic bowel syndromes requires further proof before this should be considered as a positive test for IBS."
They conclude, "Nonetheless, their experimental model has potential to explore dietary and pharmacological approaches to resolve problems of gas and fat intolerance in patients."