1 University of Monterrey (UDEM), Monterrey, México; 2 Wageningen Univeristy (WUR), Netherlands; 3 Institute of Food, Nutrition and Health (ETH Zürich), Switzerland; 4 National Institute of Public Health of Mexico (INSP), México.
Background: Iron deficiency is common in obese subjects. This may be due to adiposity-related inflammation increasing serum hepcidin and decreasing iron absorption. Aim: We evaluated whether weight and fat loss in obese subjects would decrease inflammation and serum hepcidin and thereby improve iron absorption. Methods: We performed a 6-month, prospective study in obese (body mass index (BMI), =35<45 kg/m2) adults who had recently undergone laparoscopic sleeve-gastrectomy. At 2 months and 8 months post-surgery, subjects consumed a test drink with 6mg 57Fe as ferrous sulphate and were intravenously infused with 100 μg 58Fe as iron citrate. We compared erythrocyte incorporation of iron isotopic labels, changes in body composition, iron status, hepcidin and inflammation at 2 and 8 months. Results: Of 43 subjects studied at baseline, 38 completed the protocol (32 women, 6 men). After 6 months, total body fat (TBF%), inflammation and hepcidin were significantly lower (all, P<0.005). In iron-deficient subjects (n=17), geometric mean (95%CI) iron absorption significantly increased (from 9.7% (6.5-14.6) to 12.4% (7.7-20.1) (P=0.03), while in iron sufficient subjects (n=21), it did not change (5.9% (4.0-8.6) and 5.6% (3.9- 8.2)) (P=0.81)). In all subjects, there was a non-significant increase in iron absorption (7.3% at 2 months vs. 8.0% at 8 months, P=0.37). Conclusion: Our findings suggest adiposity-related inflammation reduces the normal up-regulation of iron absorption in iron-deficient obese subjects, and that this adverse effect is ameliorated by fat loss.