Brohée Lecture at Gastro 2009 - Acid secretion in the developed world - now too much of a good thing ?

There has been a remarkable change in the human stomach in the western world over the past few decades. Fifty years agO. most adults in the western world had their stomach colonized by Helicobacter pylori infec- tion. The associated chronic mucosal inflammation caused a progressive loss of specialized parietal cells and a consequent reduction in acid secretion with increasing age. H. pylori has colonized the human stomach since at least the time our ancestors migrated from Africa 65,000 years ago (Fig. 1). Diminution in acid secretion with increasing age has therefore been a feature of the stomach since as long ago as we know. The very recent disappearance of H. pylori infection means that acid secretion is maintained throughout life and is thus now substantially higher in adults than it was in previous generations. One important question that needs to be addressed is whether the new pattern of acid secretion is suited to our current environment in the western world.