Acid Reducing Meds Linked to Low Vitamin B12 Levels

Proton pump inhibitors and H2RAs associated with vitamin B12 deficiency in new study

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) It's relatively common for older folks to have low levels of vitamin B12. According to a new study, certain medications may contribute to these low vitamin levels.

In this new study, two medications commonly used to reduce stomach acid in older people were linked to first-time diagnoses of dangerously low levels of vitamin B12.

"Ask your doctor about safely reducing excess stomach acid."

Jameson R. Lam, MPH, of Kaiser Permanente health care system in Oakland, CA, was lead author of this study.

The study examined the potential link between vitamin B12 deficiency and two medications used to reduce excess stomach acid. Those medications are known as proton pump inhibitors (PPIs) and histamine 2 receptor antagonists (H2RAs).

To investigate the potential link, these researchers analyzed the medical records of 25,956 residents of northern California who were newly diagnosed with vitamin B12 deficiency between January 1997 and June 2011. The study also analyzed records of 184,199 northern California patients who were not deficient in B12 during those same years. Most of the patients in both groups were 60 years or older. Almost half of them were women.

Of the 25,956 patients diagnosed with vitamin B12 deficiency, 3,120 patients (12 percent) had been prescribed PPIs for at least two years. Also, 1,087 patients (4.2 percent) of patients in that same group were given two or more years' worth of H2RAs but did not use PPIs. The remaining 21,749 patients (83 percent) did not take either of the two acid-reducing medications.

Of the 184,199 patients in the second group, 13,210 individuals (7.2 percent) had been prescribed at least two years' worth of PPIs. And 5,897 patients (3.2 percent) had been given at least two years' worth of H2RAs but did not use PPI. The remaining 165,092 patients (89.6 percent) took neither PPIs nor H2RAs.

Given those findings, these researchers concluded that receiving two or more years’ worth of PPIs and H2RAs raised the risk for vitamin B12 deficiency.

Patients who took PPIs for at least two years had 1.65 greater odds of becoming deficient in B12 than people who did not take PPIs.

Those taking H2RAs for at least two years had 1.25 greater odds of becoming B12 deficient than people who did not take H2RAs.

The risk was higher among people taking 1.5 PPI pills a day than among those taking three quarters of a pill per day. Patients taking at least 1.5 PPI pills daily had 1.95 greater odds of becoming B12 deficient than patients who didn't take PPIs. Patients taking three-quarters of a PPI pill daily had 1.63 greater odds of developing the deficiency.

PPIs are stronger than H2RAs.

Nevertheless, these researchers wrote that they do not recommend that persons who need and are prescribed acid-reducing medications stop taking them. "But clinicians should exercise appropriate vigilance when prescribing these medications and use the lowest possible effective dose. These findings should inform discussions contrasting the known benefits with the possible risks of using these medications,” the authors of this study wrote.

Also, these researchers found that women and younger persons in the study who took PPIs instead of the less strong H2RAs were at higher risk of becoming deficient in B12. Their risks for low B12 levels fell after they stopped taking the medication.

Healthy levels of stomach acid actually help the body to absorb B12 found in foods and supplements.

These researchers focused on the link between acid-reducing medications and vitamin B12 because deficiencies in B12 "are relatively common, especially among older adults," and as high as 15 percent among people aged 50 and older, they wrote.

"Left untreated, vitamin B12 deficiency can lead to dementia, neurologic damage, anemia, and other complications, which may be irreversible," the researchers wrote.

This study was published online December 11 in JAMA.

A grant from Kaiser Permanente Community Benefit program funded the study. One of the study's researchers has received a grant or has a grant application pending with pharmaceutical maker Pfizer.

Review Date: 
December 9, 2013
Last Updated:
December 11, 2013