Influence of diet and supplements on iron status after gastric bypass surgery

Background Iron deficiency is common after Roux-en-Y gastric bypass (RYGB) surgery, but there is no consensus on the optimal diet quality and quantity for restoring and preserving iron status. Objectives The authors explored the impact of dietary and supplemental sources of iron and absorptive factors on iron status. Setting Academic, United States. Methods In a cross-sectional cohort of individuals who underwent RYGB, nutrient intakes from food and supplements were measured using 3-day food records. Blood biomarkers of iron status, including concentrations of ferritin, total iron binding capacity, serum transferrin receptor (sTfR), and the sTfR:ferritin ratio, were assessed by a reference laboratory; iron deficiency was defined as having at least 2 abnormal measures. Associations between iron status biomarkers and dietary predictors were determined using regression analysis. Results Of the 36 participants, 97% were female, the mean age was 45 years (95% confidence interval, 41-48 years), and body mass index was 32 (30-35) kg/m². Iron deficiency was found in 42% of participants. Dietary intake of heme iron, found in meats, was favorably associated with 3 iron status biomarkers (ferritin, β =.366; sTfR:ferritin ratio, β = -.459; and total iron binding capacity, β = -18.26; all P<.05), independent of obesity-induced inflammation. Intake of Vitamin C from food contributed to iron status (ferritin, β =.010 and sTfR:ferritin ratio, β = -.011; P<.05). Use of supplementary non-heme iron, at doses recommended for prophylaxis (45 mg/d), was positively associated with serum ferritin (β =.964; P =.029). Conclusions For patients who have undergone RYGB, consuming high, but realistic amounts of heme iron in meat, Vitamin C from food, and adherence to recommended iron supplements can prevent iron deficiency.