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



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.


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.


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).


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

This is a preview of subscription content, access via your institution.

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

Fig. 1
Fig. 2
Fig. 3
Fig. 4


  1. 1.

    WHO information sheet and obesity and overweight. 2003

  2. 2.

    Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults-the evidence report. National Institutes of Health. Obes Res. 1998;6(Supp 2):51S–209S.

    Google Scholar 

  3. 3.

    Shah M, Simha V, Garg A. Long term impact of bariatric surgery on body weight, comorbidities, and nutritional status. J Clin Endocrinol Metab. 2006;91:4223–31.

    CAS  Article  Google Scholar 

  4. 4.

    North American Association for the study of obesity and the National Heart, Lung, and Blood Institute (2000) The practice guide: identification, evaluation, and treatment of overweight and obesity in adults. NIH publication 00-4084

  5. 5.

    National Task Force on the Prevention and Treatment of Obesity. Overweight, obesity, and health risk. Arch Intern Med. 2000;160:898–904.

    Article  Google Scholar 

  6. 6.

    Eckel RH. Non surgical management of obesity. N Engl J Med. 2008;358:1941–50.

    CAS  Article  Google Scholar 

  7. 7.

    Steinbrook R. Surgery for severe obesity. NEJM. 2004;350:1075–9.

    CAS  Article  Google Scholar 

  8. 8.

    Byrne TK. Complications of surgery for obesity. Surg Clin North Am. 2001;81:1181–93.

    CAS  Article  Google Scholar 

  9. 9.

    Santry HP, Gillen DL, Lauderdale DS. Trends in bariatric surgical procedures. JAMA. 2005;294:1909–17.

    CAS  Article  Google Scholar 

  10. 10.

    Waters GS, Pories WJ, Swanson MS, et al. Long term studies of mental health after the Greenville gastric bypass operation for morbid obesity. Am J Surg. 1991;161:154–7.

    CAS  Article  Google Scholar 

  11. 11.

    Balsiger BM, Kennedy FP, Abu-Lebdeh HS, et al. Prospective evaluation of Roux-en-Y gastric bypass as primary operation for medically complicated obesity. Mayo Clin Proc. 2000;75:673–80.

    CAS  Article  Google Scholar 

  12. 12.

    Sjostorm L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med. 2004;351:2683–93.

    Article  Google Scholar 

  13. 13.

    Sujerman HJ, Wolfe LG, Sica DA, et al. Diabetes and hypertension in severe obesity and effects of gastric bypass induced weight loss. Ann Surg. 2003;237:751–6.

    Google Scholar 

  14. 14.

    MacDonald KG Jr, Long SD, Swanson MS, et al. The gastric bypass operation reduces the progression and mortality of non-insulin-dependent diabetes mellitus. J Gastrointest Surg. 1997;1:213–20.

    Article  Google Scholar 

  15. 15.

    Flum DR, Dellinger EP. Impact of gastric bypass on survival: a population based analysis. J Am Coll Surg. 2004;199:543–51.

    Article  Google Scholar 

  16. 16.

    Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg. 2004;240:416–23.

    Article  Google Scholar 

  17. 17.

    Karlsson J, Sjostrom L, Sullivan M. Swedish Obese Subjects (SOS): an intervention study of obesity: two-year follow-up of health-related quality of life (HRQL) and eating behavior after gastric surgery for severe obesity. Int J Obes Relat Metab Disord. 1998;22:113–26.

    CAS  Article  Google Scholar 

  18. 18.

    Asplin JR, Coe FL. Hyperoxaluria in kidney stone formers treated with modern bariatric surgery. J Urol. 2007;177:565–9.

    Article  Google Scholar 

  19. 19.

    Nelson WK, Houghton SG, Milliner DS, et al. Enteric hyperoxaluria, nephrolithiasis, and oxalate nephropathy: potentially serious and unappreciated complications of Roux-en-Y gastric bypass. Surg Obes Relat Dis. 2005;1:481–5.

    Article  Google Scholar 

  20. 20.

    Sinha MK, Collazo-Clavell ML, Rule A, et al. Hyperoxaluric nephrolithiasis is a complication of Roux-en-Y gastric bypass surgery. Kidney Int. 2007;72:100–7.

    CAS  Article  Google Scholar 

  21. 21.

    Patel BN, Passman CM, Fernandez A et al. (2007) Prevalence of hyperoxaluria after modern bariatric surgery. Presented at 25th World Congress of Endurology & SWL 2007

  22. 22.

    Prisco CD, Levine SN. Metabolic bone disease after gastric bypass surgery for obesity. Am J Med Sci. 2005;329:57–61.

    Article  Google Scholar 

  23. 23.

    Goldner WS, O’Dorisio TM, Dillon JS, et al. Severe metabolic bone disease as a long-term complication of obesity surgery. Obes Surg. 2002;12:685–92.

    Article  Google Scholar 

  24. 24.

    Johnson JM, Maher JW, DeMaria EJ, et al. The long term effects of gastric bypass on Vitamin D metabolism. Ann Surg. 2006;243:701–5.

    Article  Google Scholar 

  25. 25.

    Coates PS, Fernstrom JD, Fernstrom MH, et al. Gastric bypass surgery for morbid obesity leads to an increase in bone turnover and a decrease in bone mass. J Clin Endocrinol Metab. 2004;89:1061–5.

    CAS  Article  Google Scholar 

  26. 26.

    Von Mach MA, Stoeckli R, Bilz S, et al. Changes in bone mineral content after surgical treatment of morbid obesity. Metabolism. 2004;53:918–21.

    Article  Google Scholar 

  27. 27.

    Goode LR, Brolin RE, Chowdhury HA, et al. Bone and gastric bypass surgery: effects of dietary calcium and vitamin D. Obes Res. 2004;12:40–7.

    CAS  Article  Google Scholar 

  28. 28.

    Basha B, Rao S, Han ZH, et al. Osteomalacia due to vitamin D depletion: neglected consequence of intestinal malabsorption. Am J Med. 2000;108:296–300.

    CAS  Article  Google Scholar 

  29. 29.

    Slater GH, Ren CF, Siegel N, et al. Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery. Gastrointest Surg. 2004;8:48–55.

    Article  Google Scholar 

  30. 30.

    Cifuentes M, Riedt CS, Brolin RE, et al. Weight loss and calcium intake influence calcium absorption in overweight postmenopausal women. Am J Clin Nutr. 2004;80:123–30.

    CAS  Article  Google Scholar 

  31. 31.

    Recker RR. Calcium absorption and achlorohydria. N Engl J Med. 1985;313:70–3.

    CAS  Article  Google Scholar 

  32. 32.

    Pak CYC, Poindexter J, Finlayson B. A model system for assessing physicochemical factors affecting calcium absorbability from the intestinal tract. J Bone Miner Res. 1989;4:119–27.

    CAS  Article  Google Scholar 

  33. 33.

    Pak CY, Avioli LV. Factors affecting absorbability of calcium from calcium salts and food. Calcif Tissue Int. 1988;43:55–60.

    CAS  Article  Google Scholar 

  34. 34.

    Straub DA. Calcium supplementation in clinical practice: a review of forms, doses, and indications. Nutr Clin Pract. 2007;22:286–96.

    Article  Google Scholar 

  35. 35.

    Malone M. Recommended nutritional supplements for bariatric surgery patients. Ann Pharmacother. 2008;42(12):1851–1858.

    CAS  Article  Google Scholar 

  36. 36.

    Hunt JN, Johnson C. Relation between gastric secretion of acid and urinary excretion of calcium after oral supplements of calcium. Dig Dis Sci. 1983;28:417–21.

    CAS  Article  Google Scholar 

  37. 37.

    Heller HJ, Stewart A, Haynes S, Pak CYC. Pharmacokinetics of calcium absorption from two commercial calcium supplements. Am J Clin Pharmacol. 1999;39:1151–4.

    CAS  Google Scholar 

  38. 38.

    Fleischer J, Stein EM, Bessler M, et al. The decline in Hip Bone Density after Gastric Bypass surgery is associated with extent of weight loss. J Clin Endocrinol Metab. 2008;93:3735–40.

    CAS  Article  Google Scholar 

  39. 39.

    Gagner M, Rogula T, Strain G, et al. Decreased Lipid malabsorption in both gastric bypass and biliopancreatic diversion with duodenal switch. Surg Obes Relat Dis. 2005;1(3):240–1.

    Article  Google Scholar 

  40. 40.

    Reidt CS, Brolin RE, Sherell RM, et al. True fractional calcium absorption is decreased after Roux-en-Y Gastric Bypass surgery. Obesity. 2006;11:1940–8.

    Article  Google Scholar 

  41. 41.

    Sakhaee K, Maalouf NM, Abrams SA, et al. Effects of potassium alkali and calcium supplementation on bone turnover in postmenopausal women. J Clin Endocrinol Metab. 2005;90:3528–33.

    CAS  Article  Google Scholar 

  42. 42.

    Kenny AM, Prestwood KM, Biskup B, et al. Comparison of the effects of calcium loading with calcium citrate or calcium carbonate on bone turnover in postmenopausal women. Osteoporos Int. 2004;15:290–4.

    CAS  Article  Google Scholar 

Download references


This work was supported by the National Institute of Health (NIH) grants MO1-RR00633 and CTSA UL1-RR024982. The authors would like to acknowledge the editorial assistance of Ms. Hadley Armstrong.

Author information



Corresponding author

Correspondence to K. Sakhaee.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Tondapu, P., Provost, D., Adams-Huet, B. et al. Comparison of the Absorption of Calcium Carbonate and Calcium Citrate after Roux-en-Y Gastric Bypass. OBES SURG 19, 1256–1261 (2009).

Download citation


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