Iron absorption and iron status are reduced after Roux-en-Y gastric bypass

Abstract

Background: Iron deficiency and iron deficiency anemia are common 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 ± 9.8 y; weight: 115.1 ± 15.6 kg, body mass index (BMI: in kg/m2); 45.2 ± 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-one individuals 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 of the 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. © 2009 American Society for Nutrition.