Assessment of Ferrous Sulfate Contribution to Oxidative Stress in Post‐bariatric Surgery Patients with Iron Deficiency

Abstract

Obesity is a global public health problem with numbers of affected people increasing despite the policy efforts1‐3 Bariatric surgery is the common treatment for patients with severe obesity, with increasing number of patients undergoing the surgery (252,000 in 2018 to 256,000 in 2019).4 Unfortunately, 10‐60% of patients develop iron deficiency after the bariatric surgery.5, 6 High‐dose oral iron (i.e., 150‐200 mg of non‐heme iron supplement such as FeSO47) is a recommended treatment for patients with iron deficiency anemia (IDA) in post‐bariatric surgery patients.7 Studies show that oxidative stress (OxS) is an adverse effect of high dose oral iron therapy8, therefore we hypothesized that patients undergoing supplementation with high dose FeSO4 would exhibit increases in systemic oxidative stress. We tested our hypothesis with a secondary analysis using archived plasma specimens from a randomized, single‐blind study that included an arm that underwent treatment with high dose oral FeSO4and a comparison group that underwent a novel heme iron supplement (heme‐iron‐polypeptide, HIP). Participants were women who had developed IDA after bariatric surgery and findings of the study demonstrated superiority of high dose FeSO4 for 8 weeks for improving iron status.9 At baseline, the mean ± standard deviation for age, BMI, and years since surgery of the sample was 39.2 ± 8.7 years, 31.4 ± 7.2 kg/m2, and 6.9 ± 3.1 years, respectively. We used plasma from participants without obesity or bariatric surgery as a control group. We measured malondialdehyde (MDA), an established biomarker of oxidative stress (Abcam, UK). The two‐way ANOVA (IBM SPSS 27) showed no significant difference in mean MDA levels. Mean MDA values for FeSO4, HIP, and control group were 65.4 ± 38.3, 98.70 ± 63.4, and 84.9 ± 60.7 pmol/mL, respectively (all p>0.05).ConclusionsOur findings of no difference in change in oxidative stress between groups does not support our hypothesis that high dose oral iron increases OxS. Limitations of our study are the small sample size and future clinical studies need to determine the potential of oxidative following high dose oral iron therapy in bariatric surgery patients with IDA.