Comparison of the absorption of calcium carbonate and calcium citrate after roux-en-Y gastric bypass

P. Tondapu, D. Provost, B. Adams-Huet, T. Sims, C. Chang, K. Sakhaee

Research output: Contribution to journalArticlepeer-review

93 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1256-1261
Number of pages6
JournalObesity Surgery
Issue number9
StatePublished - Sep 2009


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

ASJC Scopus subject areas

  • Surgery
  • Endocrinology, Diabetes and Metabolism
  • Nutrition and Dietetics


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