Ruz, M. et al. Iron absorption and iron status are reduced after Roux-en-Y gastric bypass. Am. J. Clin. Nutr. 90, 527-532

Department of Nutrition, University of Chile, Santiago, Chile.
American Journal of Clinical Nutrition (Impact Factor: 6.77). 08/2009; 90(3):527-32. DOI: 10.3945/ajcn.2009.27699
Source: PubMed


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.
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.
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/m(2)); 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.
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.
Iron absorption is markedly reduced after RYGBP with no further modifications, at least until 18 mo after surgery.

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    • "Concerning iron homeostasis, despite the delayed response to the oral iron dose after surgery, no statistically significant differences in the total iron plasma response were observed during the 4-hour period. Ruz et al. [30] showed a reduction of 40.3% in iron absorption from a standard dose of ferrous ascorbate 6 months after surgery. "
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    ABSTRACT: The duodenum and proximal jejunum are excluded after Roux-en-Y gastric bypass but these intestinal sites are where iron and zinc are most absorbed. Therefore, they are among the nutrients whose digestive and absorptive process can be impaired after surgery. The aim of the present study was to investigate the iron and zinc plasma response to a tolerance test before and after bariatric surgery. The study was performed at São Paulo University School of Medicine of Ribeirão Preto, Brazil. In a longitudinal paired study, 9 morbidly obese women (body mass index ≥40 kg/m(2)) underwent an iron and zinc tolerance test before and 3 months after surgery. The iron and zinc levels were determined at 0, 1, 2, 3, and 4 hours after a physiologic unique oral dose. The mineral concentrations in the plasma and 24-hour urine sample were assayed using an atomic absorption spectrophotometer. The anthropometric measurements and 3-day food record were also evaluated. A linear mixed model was used to compare the plasma concentration versus interval after the oral dose, before and after surgery. The pre- and postoperative test results revealed a significantly lower plasma zinc response (P <.01) and a delayed response to iron intake after surgery. The total plasma iron concentration area, during the 4 hours, was not different after surgery (P >.05). The 24-hour urinary iron and zinc excretion did not differ between the pre- and postoperative phases. The present data showed a compromised response to the zinc tolerance test after gastric bypass surgery, suggesting an impaired absorption of zinc. More attention must be devoted to zinc nutritional status after surgery.
    Full-text · Article · Mar 2011 · Surgery for Obesity and Related Diseases
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    • "Greatly reduced stomach capacity strictly limits hydrochloric acid and protease secretion, which are required to hydrolyze heme iron from proteins. Reduction in intestinal absorption surface area after gastric bypass consequently results in less iron absorption capacity, as absorption is highest in the duodenum and initial portions of the jejunum (Gropper et al., 2009; Ruz et al., 2009). Prolonged deficiency ultimately manifests as iron deficiency anemia, which results in skin pallor, fatigue, impaired cognitive performance, decreased work productivity, and decreased resistance to infection (Gropper et al., 2009). "
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    ABSTRACT: The most effective method of sustainable weight loss in obese patients is bariatric surgery. However, micronutrient deficiencies that can result after bariatric surgery can cause health problems that may outweigh its benefits. Micronutrient deficiencies are most common in patients who undergo Roux-en-Y gastric bypass or biliopancreatic diversion with or without duodenal switch. The majority of vitamin B12 and folate deficiencies studies showed significant prevalence rates in their patient populations. Most concluded that routine oral B12 supplementation was ineffective at resolving deficiency; very high oral doses (> 350 μg) or intramuscular injections of crystalline B12 were typically required. Studies of iron deficiency after bariatric surgery found high prevalence rates due to inadequate oral supplementation, which can lead to the need for parenteral supplementation. Calcium and vitamin D deficiency studies also showed high prevalence rates of deficiency, which is important to address as deficiency can result in metabolic bone disease. Overall, the need for lifelong supplementation and follow up, early detection of deficiencies, patient education, and more aggressive supplementation regiments were emphasized to increase quality of life in bariatric surgery patients. Future research in bariatric surgery studies should include long-term health outcomes, patient education on required supplementation, and more aggressive supplementation regimens.
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