title: Effects of Chili Treatment on Gastrointestinal and Rectal Sensation in Diarrhea-predominant Irritable Bowel Syndrome: A Randomized, Double-blinded, Crossover Study.
abstract: OBJECTIVE
  Whether, chronic chili ingestion can desensitize transient receptor potential vanilloid type 1 receptors in gastrointestinal (GI) tract leading to decrease GI symptoms and sensation in diarrhea-predominant irritable bowel syndrome (IBS-D) patients has not been well explored. The aim of this study was to determine the effects of 6-week chili treatment on postprandial GI symptoms and rectal sensation in response to balloon distention in IBS-D patients.
  
  
  METHODS
  Sixteen IBS-D patients received placebo or chili capsules before meals 3 times/day for 6 weeks in a randomized, double-blinded, crossover fashion with 4-week washout period. Postprandial GI symptoms were evaluated. All patients underwent a rectal barostat study to evaluate rectal sensory threshold at the end of each treatment.
  
  
  RESULTS
  The maximum postprandial abdominal burning scores were similar between both treatments at baseline (1.4 [0.0-2.0] vs. 1.1 [0.0-2.8], P > 0.05) but were significantly decreased after chili (0.0 [0.0-0.5] vs. 0.3 [0.0-1.6], P < 0.05) at the end of treatment. The chili treatment significantly increased sensory threshold for the first rectal sensation (median [interquartile range]:16 [12-16] mmHg vs. 8 [8-16] mmHg, P < 0.05) however, there was no significant effect on rectal compliance (7.3 ± 1.0 vs. 7.1 ± 1.8 mL/mmHg). Other postprandial GI symptoms did not vary significantly between both treatments at baseline and the end of treatment.
  
  
  CONCLUSIONS
  In IBS-D patients, 6-week chili ingestion significantly decreased postprandial abdominal burning and increased the rectal sensory threshold. These findings suggest a desensitization effect of chili ingestion on transient receptor potential vanilloid type 1 receptors in the proximal gut and rectum.
authors.affiliation: Gastrointestinal Motility Research Unit, Division of Gastroenterology, Department of Internal Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Satimai
authors.initials: S
authors.lastname: Aniwan
authors.affiliation: Gastrointestinal Motility Research Unit, Division of Gastroenterology, Department of Internal Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Sutep
authors.initials: S
authors.lastname: Gonlachanvit
keywords: Capsaicin, Gastrointestinal tract, Irritable bowel syndrome, Sensation