Introduction: The ingestion of capsules containing capsaicin, the pungent ingredient of chili pepper,
induces more intense upper GI sensations in patients with non ulcer dyspepsia (NUD)
than in health, in patients with inflammatory bowel disease (IBD), peptic ulcer disease
(PUD), and other GI disorders. Whether this is due to chemical hypersensitivity or
hypervigilance is yet not clear.
Aims: 1) to further evaluate whether oral ingestion of capsaicin containing capsules ('capsaicin
test') induces more symptoms in patients with NUD than in health and in patients with
upper GI symptoms of other origin. 2) to determine whether in NUD patients the symptoms
induced by the ingestion of capsaicin capsules are due to chemical hypersensitivity
or hypervigilance.
Methods: N=200 outpatients (73 NUD, 26 IBD, 23 PUD, 36 irritable bowel syndrome (IBS) and
42 other diseases) and N=86 healthy controls swallowed a capsule containing 0,75mg
capsaicin after an overnight fast. Subjects completed a graded questionnaire evaluating
intensity of 9 different upper GI symptoms (5 grades per symptom) before and 30 minutes
after capsule ingestion. Symptom scores were summarized and a score difference (score
after minus score before capsule ingestion) was calculated; according to previous
findings, a score difference >9 was considered as positive test. Additional N=20 healthy
subjects and N=13 NUD patients who had a positive test received a second capsule containing
placebo. NS=not significant.
Results: Score difference in NUD was 9.5±6.2, i.e. significantly higher than in PUD (1.9±5.0,
p<0.001), IBD (4.5±4.7; p<0.01), IBS (5.2±4.9; p<0.05) and 'other GI disorders' (2.9±3.4;
p<0.001), as well as healthy controls (6.5±4.3; p<0.001). 51% of patients with NUD
had a positive test, 49% a negative test. The result of the capsaicin test was independent
of the subgroup of NUD (pain or discomfort predominant). Healthy subjects (n=20) had
a symptom score of 1.0±1.9 when receiving placebo and 2.5±2.1 after capsaicin. NUD
patients (n=13) had a score difference of 2.0±1.7 after placebo (NS vs. health) and
15.8±2.6 after capsaicin. No patient had a positive test after placebo.
Conclusion: Capsaicin induces symptoms in patients with NUD due to chemical hypersensitivity rather
than hypervigilance (no reaction to placebo). Chemical hypersensitivity discriminates
functional disorders from healthy controls and patients with other upper GI disorders.
The capsaicin test is a simple and non invasive method to detect a subgroup of functional
dyspepsia with chemical hypersensitivity. Targeting the VR1 receptor might be a therapeutic
option in a large subgroup of patients with functional dyspepsia.
