Can excess intestinal fermentation gas and abdominal distension worsen belching and gastroesophageal reflux?

Gastrointestinal gas accumulation and abdominal distension play a major role in modulating upper gastrointestinal mechanics and motor reflexes, directly impacting reflux pathology.

Mechanistic pathways of fermentation and pressure

• Intestinal fermentation of poorly absorbed carbohydrates produces excess gas (such as hydrogen, methane, and carbon dioxide), resulting in abdominal distension.
• This localized distension elevates overall intra-abdominal pressure, which is directly transmitted to the gastric cavity, raising intragastric pressure.
• Increased pressure within the stomach compromises the gastroesophageal pressure gradient and shortens the abdominal segment of the lower esophageal sphincter (LES), lowering its baseline tone.

Triggering of TLESRs and reflux symptoms

• Gastric wall stretch from transmitted pressure triggers a vago-vagal reflex mediated by stretch-sensitive mechanoreceptors in the proximal stomach, increasing the frequency of transient lower esophageal sphincter relaxations (TLESRs).
• TLESRs serve as the primary physiological motor mechanism for the retrograde movement of gastric contents.
• Under high intragastric pressure, a TLESR allows rapid backflow of acid and gas into the esophagus, which clinically manifests as worsened heartburn, acid regurgitation, and repetitive belching.

Bottom line

• Excess intestinal gas and abdominal distension increase intragastric pressure and trigger TLESRs, which compromise the gastroesophageal barrier to drive acid reflux and belching.