Effects of proton pump inhibitors on calcium carbonate absorption in women: A randomized crossover trial

Higher calcium intakes have been associated with decreased bone loss,(1) and lower calcium absorption has been associated with increased fracture risk.(2) Because the average American diet contains insufficient calcium,(3) Most Americans require calcium supplementation.(4) The role of pH in calcium absorption is controversial and confounded by food effects, which alter stomach pH and gastrointestinal motility. In vitro calcium carbonate disintegration and dissolution is pH dependent; as pH increases, disintegration and dissolution slows, decreasing from 96% at a pH of 1, to 23% at pH 6.1.(5) Proton pump inhibitors effectively reduce gastric acid production and increase gastric pH. In a recent study, daily omeprazole increased the me- than stomach pH from 1.3 to 5.5,(6) with 19% of the day spent above a pH of 6.(7) Therefore, the purpose of this study was to determine if acid suppression from proton pump inhibitors would decrease calcium absorption.