Iron Absorption And Iron Status Are Reduced After Roux-En-Y Gastric

Iron absorption and iron status are reduced after Roux-en-Y gastric bypass1–3
Manuel Ruz, Fernando Carrasco, Pamela Rojas, Juana Codoceo, Jorge Inostroza, Annabella Rebolledo, Karen Basfi-fer, Attila Csendes, Karin Papapietro, Fernando Pizarro, Manuel Olivares, Lei Sian, Jamie L Westcott, K Michael Hambidge, and Nancy F Krebs
ABSTRACT Background: Iron deficiency and iron deficiency anemia arecommon in patients who undergo gastric bypass. The magnitude of change in iron absorption is not well known. Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on iron status and iron absorption at different stages after surgery. We hypothesized that iron absorption would be markedly impaired immediately after surgery and would not improve after such a procedure.Design: Anthropometric, body-composition, dietary, hematologic, and iron-absorption measures were determined in 67 severe and morbidly obese women [mean age: 36.9 6 9.8 y; weight: 115.1 6 15.6 kg, body mass index (BMI: in kg/m2); 45.2 6 4.7] who underwent RYGBP. The Roux-en-Y loop length was 125–150 cm. Determinations were carried out before and 6, 12, and 18 mo after surgery. Fifty-oneindividuals completed all 4 evaluations. Results: The hemoglobin concentration decreased significantly throughout the study (repeated-measures analysis of variance). The percentage of anemic subjects changed from 1.5% at the beginning of the study to 38.8% at 18 mo. The proportion of patients with low serum ferritin increased from 7.5% to 37.3%. The prevalence of iron deficiency anemia was 23.9% at the end ofthe experimental period. Iron absorption from both a standard diet and from a standard dose of ferrous ascorbate decreased significantly after 6 mo of RYGBP to 32.7% and 40.3% of their initial values, respectively. No further significant modifications were noted. Conclusion: Iron absorption is markedly reduced after RYGBP with no further modifications, at least until 18 mo after surgery. Am J ClinNutr 2009;90:527–32.

deficiency anemia are among the most prominent findings. Iron deficiency has been reported in 15–60% of patients who undergo gastric bypass (6–9). Although prophylactic iron supplements have been recommended for women who undergo RYGBP, there is no agreement on the amount and form of iron that could efficiently prevent the development of iron deficiency. Of the potential causes ofiron deficiency, frequently mentioned is the reduced capacity to absorb iron, but the experimental evidence to support this is limited (10). In the present study we determined iron status and iron absorption before and 6, 12, and 18 mo after RYGBP. We hypothesized that, compared with presurgical measurements, iron absorption would be significantly impaired 6 mo after surgery and that thisimpairment would persist at the subsequent follow-up time points. A secondary hypothesis was that iron deficiency would also persist after surgery, despite iron supplementation.

Downloaded from ajcn.nutrition.org by guest on February 15, 2013

SUBJECTS AND METHODS

Subjects Sixty-seven menstruating women were enrolled in this study. The mean (6 SD) age of the subjects was 36.9 6 9.9 y (range: 18–55y), weight was 115.1 6 15.6 kg (range: 88.4–156.4 kg), and body mass index (BMI; kg/m2) was 45.2 6 4.7. The patients were enrolled between August 2004 and December 2006. The subjects were evaluated before and 6, 12, and 18 mo after RYGBP (see details below). The inclusion criteria considered women with a BMI  40 or  35 with comorbidities and who
From the Department of Nutrition, Faculty ofMedicine, University of Chile, Santiago, Chile (MR, FC, PR, JC, JI, AR, and KB); the Department of Surgery, University of Chile Clinical Hospital (AC and KP), the Institute of Nutrition and Food Technology (FP and MO), University of Chile, Santiago, Chile; and the Section of Nutrition Pediatrics, University of Colorado Denver, School of Medicine, Denver, CO (LS, JLW, KMH, and NFK). 2 Supported by...