Effects of Dietary Nitrate on Oesophageal Motor Function and Gastro-Oesophageal Acid Exposure in Healthy Volunteers and Reflux Patients

Abstract

Background/Aims: High concentrations of nitric oxide (NO), derived from dietary nitrite in an acid environment, have been demonstrated in the gastric fundus and in the oesophagus. The aim of this study was to investigate whether luminal NO can influence oesophageal smooth muscle performance, lower oesophageal sphincter (LOS) function or gastric and oesophageal acid exposure. Methods: Eleven healthy volunteers and 9 patients with chronic gastro-oesophageal reflux disease (GORD) received a diet deprived of nitrate/nitrite but supplemented with placebo or potassium nitrate for 4 days in a randomised order. On day 4 in each trial period, manometry was performed including a sleeve sensor registration of the LOS followed by a simultaneous 24-hour intra-gastric and oesophageal pH registration. Results: Nitrate supplementation increased the proportion of effective peristalsis when analysed for the entire study population. No other significant effects of dietary nitrate were found on oesophageal motor variables, on the sphincter resting tone or on the number or duration of transient sphincter relaxations. No effect was found on either gastric acidity or gastro-oesophageal reflux variables. Major reflux symptoms were not influenced by nitrate administration. Conclusion: Dietary nitrate did not significantly affect oesophageal motor or LOS function, gastro-oesophageal acid reflux or reflux symptomatology either in healthy volunteers or in GORD patients.