Recently the relationship between intragastric pressure (IGP) and reflux events after a meal was investigated, both in gastro-esophageal reflux disease (GERD) patients and in healthy volunteers. Ingestion of a meal was accompanied by a drop in IGP. However, the magnitude of this drop varied and was inversely correlated with the number of transient lower esophageal sphincter relaxations (TLESRs) and the number of reflux events, both in patients and in healthy volunteers: a smaller meal-induced drop in IGP was associated with a higher rate of reflux events and vice versa. This finding suggests that a smaller meal-induced drop may act as a trigger for reflux. It has been demonstrated that bitter administration leads to a smaller meal-induced drop. Therefore, bitter can be a dietary trigger for TLESRs facilitating the occurrence of symptoms of GERD. To evaluate this hypothesis, the researchers will study the relationship between bitter and the occurrence of TLESRs and reflux events in healthy volunteers. Additionally, it has been demonstrated that administering bitter also influences the concentration of motilin. Therefore, the research team will also measure the concentration of motilin to investigate whether changes in motilin concentrations can influence the number of TLESRs, via a change in gastric tone.

Inclusion Criteria:

• Healthy female volunteers
• Age between 18 and 65
• Written informed consent

Exclusion Criteria:

• A history of any upper GI symptoms or GI surgery;
• Psychological disorders;
• Concomitant use of other medication or treatments except for oral contraceptives;
• Use of medication altering esophageal or GI motility;
• Pregnant or nursing women.