Many people with, and also without, diabetes are taking drugs called proton pump inhibitors (PPIs) for acid reflux. Examples of PPIs include omeprazole (Prilosec) and esomeprazole (Nexium).
These drugs inhibit the cells in the stomach that produce acid.
When your stomach is acidic, the secretion of a hormone called gastrin, which tells the stomach to release more acid, is inhibited. When your stomach is less acid, for example after taking a PPI, more gastrin is released.
Thus taking PPIs increases the gastrin levels in the blood. High gastrin levels can increase your risks of certain kinds of stomach cancer, but low levels of gastrin can increase the risk of others.
Now comes a study suggesting that pantoprazole, a PPI, improves glycemic control in people with diabetes. The patients in the study reduced their A1c from 7.6 to 6.8. In fact, the authors of an editorial on the topic call gastrin an incretin, albeit not a very powerful one.
The incretins are gut hormones that increase the release of insulin when your blood glucose levels increase, for example, after eating carbohydrates. Byetta is an artificial incretin that has the same effect as GLP-1 (glucagonlike peptide-1), a natural incretin.
The authors of the editorial also suggest that gastrin can induce beta-cell proliferation.
The study cited in the editorial was small, and because of the simultaneous potential of harm in some patients, I don't think anyone who doesn't have acid reflux should rush out and take PPIs. The PPIs can have other side effects, including increased numbers of fractures. The cited editorial has a good discussion of the pros and cons of PPI therapy.
However, if you're already taking a PPI and you're worried about the negative side effects like fractures and a small increase in cancer risk, it's nice to know that the drugs may also have a positive effect on your diabetes.
Determining risks vs benefits for any drug is often difficult, and it can depend on your particular physiology, other drugs you're taking, and relative risks of side effects. For example, if you're already at high risk for broken bones, you probably wouldn't want to take drugs that would increase that risk even more. A drug may have a bad side effect but it reduces your blood glucose levels, and high blood glucose levels also have bad effects.
Sometimes overworked physicians don't have time to keep up with the latest research on everything. So the more you know about potential pros and cons of any drug, the better able you'll be to work with the doctor to come up with the best therapy for you.