RELATIONSHIPS BETWEEN THE ACIDITY AND OSMOLALITY OF POPULAR BEVERAGES AND REPORTED POSTPRANDIAL HEARTBURN

Background/Aims: Although many beverages produce heartburn, the relationship between the acidity and osmolality of beverages and heartburn is unclear. The aim of this study was to relate the acidity and osmolality of beverages with their ability to cause heartburn. Methods: We measured pH, total titratable acidity, and osmolality of 38 beverages in vitro and then correlated acidity and osmolality with the amount of heartburn reported by questionnaire in 394 people with heartburn. Results: Among 17 citrus drinks and juices, titratable acidity correlated with reported heartburn scores (r = 0.65; P = 0.004). Soft drinks had the lowest pH readings of any beverages studied, and decreasing pH among soft drinks was correlated with reported heartburn scores (r = 0.82; P < 0.001). Alcoholic beverages (wines and beer), coffee, and (to a lesser extent) tea were associated with significant amounts of reported heartburn when compared with water. Milk was also associated with a modest amount of reported heartburn that was related to its fat content. Osmolality of beverages was unrelated to reported heartburn. Conclusions: High titratable acidity of citrus drinks and juices and low pH of soft drinks are associated with more reported heartburn. Our findings provide a foundation for dietary advice in patients with heartburn and reflux esophagitis.