As per the recent study, Most commonly prescribed PPI's for Acid reflux / GERD/ Acidity such as Omeprazole, Pantoprazole , Lansoprazole......are found to be helpful in controlling Blood Sugar, though it does not prevent from the risk of diabetes..
This is only a initial study and so Please don't pop up these easily available over the counter drugs unless prescribed by your doctor. These PPI's may be safe for short term , but in the long term it is not good for your overall helth. Since it reduces stomach HCL , you may end up in to malabsorption of essential nutrients such as Iron, Zinc and others. Also it is known to disturb our gut bacteria.
PPI's are also indicated for H.Pylori infection.