Can Calcium Supplements Protect Against PPI-Induced Vitamin B12 Deficiency?

Patients taking acid reducers long term are at greater risk for hypochlorhydria-induced vitamin B

12

malabsorption.

Both proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H

2

RAs) can block the activity of intrinsic factor. However, the risk is widely inconsistent across studies due to variable samples and confounding designs.

Atrophic gastritis, Crohn’s disease, celiac disease, total or partial gastrectomy, gastric surgery, pancreatectomy, pancreatitis, and ileal resection can also cause vitamin B

12

malabsorption. Calcium supplementation may reverse the effect of hypoparathyroidism and metformin-induced vitamin B

12

malabsorption.

The

Journal of Nutrition Health and Aging

recently published a study that shows calcium supplements temper gastric acid inhibitor-induced vitamin B

12

malabsorption. This retrospective cross-sectional study collected data from the Quebecois Geriatric Assessment Unit inpatients discharged from January 2008 through March 2012.

Enrolled patients received scheduled H2RA or PPI therapy upon admission. The researchers excluded patients with missing records and hospital stays shorter than 5 days. The prevalence of vitamin B

12

deficiency in this cohort (41.3%) was similar to that seen in other studies enrolling patients in rehabilitation units.

Previous studies have shown that calcium chelators decrease intestinal vitamin B

12

absorption. No research has shown that PPIs or H

2

RAs have chelating actions, but PPIs limit absorption of calcium carbonate, the most commonly used calcium supplement.

Quite by accident, the researchers found that patients taking PPIs (but not H

2

RAS) without concomitant calcium supplements were more likely to have vitamin B

12

deficiency than those taking PPIs plus calcium. This indicated that calcium modifies the effect of PPIs significantly.

In the study, calcium supplements protected patients from the effect of gastric acid reducers. Inconsistent prevalence of calcium supplement co-administration between studies can explain the variable risk of vitamin B

12

absorption.

The researchers concluded that calcium supplements reduce the vitamin B

12

malabsorption effect of gastric acid reducers. They believe future studies should consider calcium supplement co-administration to be a confounder in the risk of vitamin B

12

malabsorption.