Do proton pump inhibitors decrease calcium absorption?

Abstract

Proton pump inhibitors (PPIs) increase osteoporotic fracture risk presumably via hypochlorhydria and consequent reduced fractional calcium absorption (FCA). Existing studies provide conflicting information regarding the direct effects of PPIs on FCA. We evaluated the effect of PPI therapy on FCA. We recruited women at least 5 years past menopause who were not taking acid suppressants. Participants underwent three 24-hour inpatient FCA studies using the dual stable isotope method. Two FCA studies were performed 1 month apart to establish baseline calcium absorption. The third study occurred after taking omeprazole (40 mg/day) for 30 days. Each participant consumed the same foods during all FCA studies; study meals replicated subjects' dietary habits based on 7-day diet diaries. Twenty-one postmenopausal women ages 58 ± 7 years (mean ± SD) completed all study visits. Seventeen women were white, and 2 each were black and Hispanic. FCA (mean ± SD) was 20% ± 10% at visit 1, 18% ± 10% at visit 2, and 23% ± 10% following 30 ± 3 days of daily omeprazole (p = .07, ANOVA). Multiple linear regression revealed that age, gastric pH, serum omeprazole levels, adherence to omeprazole, and 25-hydroxyvitamin D levels were unrelated to changes in FCA between study visits 2 and 3. The 1,25-dihydroxyvitamin D3 level at visit 2 was the only variable (p = .049) associated with the change in FCA between visits 2 and 3. PPI-associated hypochlorhydria does not decrease FCA following 30 days of continuous use. Future studies should focus on identifying mechanisms by which PPIs increase the risk of osteoporotic fracture. © 2010 American Society for Bone and Mineral Research.

American Association of Clinical Endocrinologists and American College of Endocrinology Disease State Clinical Review: Postoperative Hypoparathyroidism - Definitions and Management

“…Calcium carbonate (40% elemental calcium) or calcium citrate (21% elemental calcium) are most commonly prescribed and should be taken with meals. The solubility of calcium carbonate is dependent upon acidification, and achlorhydria may impede absorption; however, this is controversial (43). Patients on a proton pump inhibitor or elderly subjects with achlorhydria should be at least initially treated with calcium citrate, which does not require an acidic environment for absorption.…”

The impact of medication on vitamin D status in older individuals

“…However, information about the relationship with serum 25(OH)D is limited. Recently published research showed no change in serum 25(OH)D after omeprazol therapy, but this study sample consisted of healthy young people and they used omeprazole for only 30 days (36).…”

Proton pump inhibitor use for 12 months is not associated with changes in serum magnesium levels: a prospective open label comparative study

“…In addition, our inability to assess vitamin D status and nutritional intake of magnesium and calcium limits the conclusion that detrimental effect on serum calcium levels is definitely attributed to PPIs. Ca carbonate consumed under fasting condition a decade ago, two other studies assessed calcium absorption using dual-stable calcium isotopes and found no changes in fractional calcium absorption, thus concluding no effect of PPI on calcium absorption and metabolism (26,27). Similarly, a recent study of Sharara et al (28) concluded no measurable effect of PPI intake on calcium metabolism.…”