The Effects Of High Or Low Iron Status And Male Or Female Sex On The Non-Transferrin-Bound Iron Response To Oral Iron Supplementation

Background: Fe status determines intestinal Fe‐absorption and internal metabolism. Recently, sex‐associated effects on Fe handling have been suggested as well. These hold implications for prophylactic or therapeutic oral Fe supplementation. Objective: To determine whether sex and/or Fe‐status influence the NTBI response to oral Fe. Methods: 40 subjects ‐‐10 men (LM) and 10 women (LW) with low Fe stores (70 µg ferritin/L) ‐‐ provided blood samples at baseline and at 90, 180 and 270 min after ingesting 100 mg Fe as FeSO4. Fe and NTBI were quantified with ferrozine‐based assay and a fluorometric competitive‐binding assay, respectively. Responses in serum were estimated as cumulative 3‐h absolute concentrations. Results: The respective ∑ 3‐h absolute concentrations (in µg/dL) were 820±124, 560±115, 714±61, and 772±198 for serum Fe (p=0.004), and 12±3, 14±4, 16±4, and 11±6 for serum NTBI (p=0.218) for the LM, AM, LW, and AW groups. Two‐way ANOVA interaction‐terms for Fe status and sex were statistically significant for the serum Fe and NTBI responses (p=0.003 and p=0.05). Conclusion: Among males, the serum Fe uptake response was diminished with adequate Fe status as compared to low status, but a corresponding status‐related differential was not seen among women. The NTBI response was equally mitigated across the entire spectrum of subject groups. Grant Funding Source : Supported by the Hildegard Grunow Foundation