Acute Effects of Red Chili, a Natural Capsaicin Receptor Agonist, on Gastric Accommodation and Upper Gastrointestinal Symptoms in Healthy Volunteers and Gastroesophageal Reflux Disease Patients

The effects of chili on gastric accommodation (GA) in gastroesophageal reflux disease (GERD) patients have not been explored. Methods: In total, 15 healthy volunteers (HV) and 15 pH-positive non-erosive GERD (NERD) patients underwent single-photon emission computed tomography after ingesting 2 g of chili or placebo in capsules in a randomized double-blind crossover fashion with a one-week washout period. GA was the maximal postprandial gastric volume (GV) after 250 mL of Ensure(®) minus the fasting GV. Upper gastrointestinal symptoms were evaluated by using a visual analog scale. Results: NERD patients but not HV had significantly greater GA after chili compared to a placebo (451 ± 89 vs. 375 ± 81 mL, p < 0.05). After chili, the postprandial GVs at 10, 20, and 30 min in NERD patients were significantly greater than HV (10 min, 600 ± 73 vs. 526 ± 70 mL; 20 min, 576 ± 81 vs. 492 ± 78 mL; 30 min, 532 ± 81 vs. 466 ± 86 mL, all p < 0.05). In NERD, chili was associated with significantly less satiety, more severe abdominal burning (p < 0.05), and a trend of more severe heartburn (p = 0.06) compared to the placebo. In HV, postprandial symptoms after chili and placebo ingestion were similar (p > 0.05). Conclusions: Chili enhanced GA in NERD patients but not in HV. This suggests that the modulation of GA in NERD is abnormal and likely involves transient receptor potential vanilloid 1 (TRPV1) sensitive pathways.