Clinical Report

Obesity Surgery

, Volume 19, Issue 9, pp 1256-1261

Comparison of the Absorption of Calcium Carbonate and Calcium Citrate after Roux-en-Y Gastric Bypass

  • P. TondapuAffiliated withDepartment of Internal Medicine, Charles and Jane Pak Center for Mineral Metabolism, UT Southwestern Medical Center
  • , D. ProvostAffiliated withProvost Bariatrics
  • , B. Adams-HuetAffiliated withDivision of Biostatistics, Department of Clinical Sciences, UT Southwestern Medical Center
  • , T. SimsAffiliated withDepartment of Internal Medicine, Charles and Jane Pak Center for Mineral Metabolism, UT Southwestern Medical Center
  • , C. ChangAffiliated withCitizens Bariatric Center
  • , K. SakhaeeAffiliated withDepartment of Internal Medicine, Charles and Jane Pak Center for Mineral Metabolism, UT Southwestern Medical Center Email author 

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Abstract

Introduction

Roux-en-Y gastric bypass (RYGB) restricts food intake. Consequently, patients consume less calcium. In addition, food no longer passes through the duodenum, the main site of calcium absorption. Therefore, calcium absorption is significantly impaired. The goal of this study is to compare two common calcium supplements in gastric bypass patients.

Method

Nineteen patients were enrolled in a randomized, double-blinded, crossover study comparing the absorption of calcium from calcium carbonate and calcium citrate salts. Serum and urine calcium levels were assessed for peak values (C max) and cumulative calcium increment (area under the curve [AUC]). Serum PTH was assessed for minimum values (PTHmin) and cumulative PTH decrement (AUC). Statistical analysis was performed using a repeated analysis of variance model.

Results

Eighteen subjects completed the study. Calcium citrate resulted in a significantly higher serum C max (9.4 + 0.4 mg/dl vs. 9.2 + 0.3 mg/dl, p = 0.02) and serum AUC (55 + 2 mg/dl vs. 54 + 2 mg/dl, p = 0.02). Calcium citrate resulted in a significantly lower PTHmin (24 + 11 pg/ml vs. 30 + 13 pg/ml, p = 0.01) and a higher AUC (−32 + 51 pg/ml vs. −3 + 56 pg/ml, p = 0.04). There was a non-significant trend for higher urinary AUC in the calcium citrate group (76.13 + 36.39 mg/6 h vs. 66.04 + 40.82, p = 0.17).

Conclusion

Calcium citrate has superior bioavailability than calcium carbonate in RYGB patients.

Keywords

Roux-en-Y gastric bypass Obesity Calcium citrate Calcium carbonate