Abstract
The pathophysiologic mechanism(s) responsible for cobalamin deficiency after Roux-en-Y gastric bypass for clinically severe obesity remains unexplained. Inadequate secretion of intrinsic factor has been postulated, but decreased gastric acid secretion resulting in maldigestion and inadequate liberation of free cobalamin from its native protein-bound form is also possible. The aim of this study was to determine prospectively secretion of gastric acid and absorption of crystalline (free) and protein-bound cobalamin before and after gastric bypass. Eight patients (two men, six women) underwent orogastric intubation of the intact stomach preoperatively and the proximal gastric pouch postoperatively. Gastric acid secretion in the basal and stimulated (pentagastrin, 6 µg/kg) states was determined by a perfused, nonabsorbable marker technique to quantitate recovery of gastric secretion. Absorption of radiolabeled (57Co) crystalline and protein-bound cobalamin was assessed on separate days by 24-hr urinary excretion. After gastric bypass, acid secretion (juvysem) was markedly reduced in basal (9.1±3.6 vs 0.005±0.003 meq/hr;P=0.04) and stimulated (12.8±1.8 vs 0.008±0.003 meq/30 min;P=0.002) states. Absorption of crystalline cobalamin was decreased (15.8±2.5 vs 9.4±1.4%;P=0.08) to a lesser extent than was protein-bound cobalamin (5.9±1.0 vs 1.1±0.3%;P=0.004). In summary, gastric acid secretion from the gastric pouch is negligible after gastric bypass, and food-bound cobalamin is maldigested and subsequently malabsorbed presumably due to pouch achlorhydria. Decreased absorption of free cobalamin suggests decreased cobalamin-intrinsic factor complex formation. This study suggests that cobalamin deficiency after Roux-en-Y gastric bypass results both from inadequate digestion of food-bound cobalamin and from insufficient secretion of intrinsic factor.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Halverson JD: Micronutrient deficiencies after gastric bypass for morbid obesity. Am Surg 52:594–598, 1986
Amaral JF, Thompson WR, Caldwell MD, Martin HF, Randall HT: Prospective hematologic evaluation of gastric exclusion surgery for morbid obesity. Ann Surg 201:186–193, 1985
Crowley LV, Olson RW: Megaloblastic anemia after gastric bypass for obesity. Am J Gastroenterol 78:406–410, 1983
Allen RH: Cobalamin (vitamin B12) absorption and malabsorption. Viewpoints Dig Dis 14:17–20, 1982
Festen HPM: Intrinsic factor secretion and cobalamin absorption: Physiology and pathophysiology in the gastrointestinal tract. Scand J Gastroenterol 26:1–7, 1991
Schilling RF, Gohdes PN, Hardie GH: Vitamin B12 deficiency after gastric bypass surgery for obesity. Ann Intern Med 101:501–502, 1984
Salom IL, Silvis SE, Doscherholmen A: Effect of cimetidine on the absorption of vitamin B12. Scand J Gastroenterol 17:129–131, 1982
Marcuard SP, Sinar DR, Swanson MS, Silverman JF, Levine JS: Absence of luminal intrinsic factor after gastric bypass surgery for morbid obesity. Dig Dis Sci 34:1238–1242, 1989
Doscherholmen A, Swaim WR: Impaired assimilation of egg Co-57 vitamin B12 in patients with hypochlorhydria and achlorhydria and after gastric resection. Gastroenterology 64:913–919, 1973
Hyden SA: A turbidimetric method for the determination of higher polyethylene glycol in biological materials. Ann R Agric Coll (Sweden) 22:139–145, 1955
Kittang E, Schjonsby H: Effect of gastric anacidity on the release of cobalamins from food and their subsequent binding to R-protein. Scand J Gastroenterol 22:1031–1037, 1987
Abels J, Schilling RF: Protection of intrinsic factor by vitamin B12. J Lab Clin Med 64:375–384, 1964
Printen KJ, Scott D, Mason EE: Stomal ulcers after gastric bypass. Arch Surg 115:525–527, 1980
Jordan JH, Hocking MP, Rout RW, Woodward ER: Marginal ulcer following gastric bypass for morbid obesity. Am Surg 57:286–288, 1991
Smith CD, Herkes SM, Behrns KE, Fairbanks VF, Sarr MG: Gastric acid secretion and its effects on vitamin B12 absorption after Roux-en-Y gastric bypass. Surg Forum 42:171–173, 1991
Author information
Authors and Affiliations
Additional information
This work was supported in part by a grant (DK39337) from the National Institutes of Health, the Ethicon Corporation, and the Mayo Foundation.
Rights and permissions
About this article
Cite this article
Behrns, K.E., Smith, C.D. & Sarr, M.G. Prospective evaluation of gastric acid secretion and cobalamin absorption following gastric bypass for clinically severe obesity. Digest Dis Sci 39, 315–320 (1994). https://doi.org/10.1007/BF02090203
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02090203