• proton pump inhibition
• intestinal microbiology

We read with great interest the recent publications in Gut by Imhann et al and Jackson et al, which assessed the impact of proton pump inhibitor (PPI) use on gut microbiota diversity and composition in humans.1 2 PPIs are one of the most commonly used drug classes worldwide. Once initiated, they are often used chronically without clear therapeutic intent.3 PPIs alter GI pH4 and delay gastric emptying rate,5 which could directly affect gut microbiota and survival of enteric pathogens. Using three independent cohorts (211 PPI users and 1604 non-users), Imhann et al 1 reported a significant decrease in alpha diversity and changes in 20% of bacterial taxa in PPI users compared with non-users. Among 1827 healthy twins, Jackson et al 2 also found a significant decrease in alpha diversity and alteration of bacterial composition in PPI users. Notably, both studies found a higher abundance of oral commensals, including Streptococcaceae …