A report published in JAMA examined the association between vitamin B12 deficiency and the length of time a patient took an acid-blocking medication.

The study included proton pump inhibitors and histamine 2 receptor antagonists, both common antacid medications.

The scientists looked at results from nearly 26,000 patients diagnosed with B12 deficiency, and compared them to more than 180,000 control subjects.

They found that those who took proton pump inhibitors for two or more years had a 65 percent higher risk of B12 deficiency.

Two or more years of a histamine 2 receptor antagonist was associated with a 25 percent increased risk of B12 deficiency.

Those who took two or more acid-blocking pills per day had a 95 percent increased risk of B12 deficiency.

If you are prescribed an antacid medication, it is best to take it for the shortest time possible. If you must be on such a medication long term, consider supplementing vitamin B12 by injection.

There is no reason to take it orally, as you need sufficient stomach acid to properly digest and absorb it.