BackgroundIron deficiency is common after gastric bypass (GB) and treatment with oral supplementation using non‐heme iron, although currently recommended, is controversial. The study objective is to compare the effectiveness of oral iron supplementation using non‐heme versus heme iron for repletion of iron deficiency.MethodsUsing a randomized, controlled, single‐blind study design, women who had GB and were iron deficient received non‐heme iron (FeSO4, 65 mg t.i.d.) or heme iron (12 mg t.i.d.). Measures of iron status, including blood concentrations of ferritin, total iron binding capacity (TIBC), soluble transferrin receptor (sTfR), and hemoglobin were determined at baseline and at 2, 4, and 8 weeks after supplementation. Data is presented as mean ± SE, or mean (95% CI).ResultsThe study is ongoing, but preliminary findings are presented herein. Baseline characteristics of screened patients (N=28) are age: 40.4±1.4 years; BMI: 34±1.4 kg/m2; time since surgery: 5.7±0.6 years; ferritin: 38.0 μg/L (16.1, 59.9); TIBC: 379 μg/dL (352, 405); sTfR: 2368.1 μg/L (1583.6, 3152.7); hemoglobin: 12.1 g/dL (11.5, 12.6). Of screened patients, 57.1% were classified as iron deficient and 35.7% had anemia. To date, 8 iron deficient patients have completed the 8‐week study (4 per group). Of those who received non‐heme iron supplementation, an improvement in blood concentrations of hemoglobin (p= 0.01), TIBC (p< 0.001), and sTfR (p= 0.049) was seen; ferritin tended to improve (p= 0.068). Of those who received heme iron supplementation, no change in iron status was seen in any of the iron status biomarkers.ConclusionEarly data demonstrate that non‐heme iron supplementation appears to be effective for repletion of iron status. Findings may guide treatment of iron deficiency, which is very common following bariatric surgery.Support or Funding InformationInternational Copper Association USDA, ARP Assistantship, to RAM