Does commercially available alkaline drinking water reduce pepsin activity?
Background: Pepsin, a key enzyme in the pathogenesis of both laryngopharyngeal and esophageal reflux disease, requires acid for its activation. Excessive acid in American diets may increase reflux disease, because pepsin is activated by a low pH (<4.6), which is found in all bottled and canned beverages. Pepsin is stable at a neutral pH and is not affected by tap and bottled drinking water. The purpose of this study was to determine whether commercially available alkaline drinking water could inactivate human pepsin.
Study design: Laboratory study.
Setting: The Voice Institute of New York.
Synopsis: Human pepsin was subjected to a stability assay to determine the effects of alkaline water on pepsin activity and recovery. Pepsin was irreversibly activated in commercially available alkaline drinking water with a pH of 8.8. Subsequent acidification did not restore activity. With no differences in pepsin activity found in comparison with control solutions of pH=7.0 without pepsin (p>0.05), determination of the buffering ability of alkaline water demonstrated that alkaline water had an eight-fold greater buffering capacity compared to commercially available bottled water as determined by the amount of acid required to reduce the pH to levels below 4.5, at which point pepsin is active.
Bottom line: Alkaline drinking water may have therapeutic benefits in the treatment of reflux disease by rendering pepsin inactive.
Reference: Koufman JA, Johnston N. Potential benefits of pH 8.8 alkaline drinking water as an adjunct in the treatment of reflux disease. Ann Otol Rhinol Laryngol. 2012;121(7):431-434.