Effect of intraduodenal fat on lower oesophageal sphincter function and gastro-oesophageal reflux

Fatty foods are commonly reported to aggravate gastro-oesophageal reflux symptoms. In this study the hypothesis that fat provokes reflux by stimulating transient lower oesophageal sphincter relaxations via small intestinal receptors was investigated.

In 12 healthy volunteers and 11 patients with reflux oesophagitis, oesophageal motility and pH were measured over 30 minute periods during which saline or fat (10% Intralipid) were infused in random order into the duodenum. The infusion periods were separated by a 30 minute washout. The stomach was loaded with 200 ml 10% dextrose, maintained by an intragastric infusion.

Fat decreased basal LOS pressure from 16.9 (SEM 2.1) to 12.4 (SEM 1.5) mm Hg in normal subjects but had no effect in patients with oesophagitis (18.8 (SEM 4.3) v 18.2 (SEM 3.0) mm Hg). During saline infusion, the rates of transient lower oesophageal sphincter relaxation and reflux episodes were greater in patients (4.5 (interquartile range 2-11)/30 min and 5 (2-14)/30 min respectively) than in controls (3 (2-4)/30 min and 3 (2-3.5)/30 min respectively). Fat increased the rate of reflux episodes in the reflux patients to 6.5 (3-25)/30 min. This effect was due to an increase in the incidence of reflux during transient LOS relaxations (65% v 91%), the rate of transient relaxations remaining unchanged.

Instillation of fat directly into the duodenum aggravates reflux in patients with reflux disease, by increasing the proportion of transient LOS relaxations accompanied by reflux.