Nanoparticles were extensively applied as carriers for bioactive compound delivery to improve their bio-availability. In this study, we developed novel water-soluble and ultra-small food-borne nanoparticles (FNs) from roasting sturgeon as carriers for Fe(ii) delivery. The molecular interactions between FNs and Fe(ii) ions, and the digestion and absorption of the FN-Fe(ii) complex through the gastrointestinal system were investigated. The thermodynamic analysis revealed that the FNs spontaneously interacted with Fe(ii) having negative Gibbs free energy change. The data showed that approximately one FN can bind with four Fe(ii) (n = 4.23) through hydroxyl and amino groups. Flow cytometric analysis indicated that the FN-Fe(ii) had no effect on the cell viability at concentration <1 mg mL-1. The FN-Fe(ii) complex was stable in the digestive tract with a retention rate of 95.18% ± 3.11% after gastrointestinal digestion. Moreover, 1 μg mm-2 FN-Fe(ii) complex could cross the intestinal wall for Fe(ii) delivery. This research revealed that FNs produced from roasted sturgeon have the potential as biocompatible, efficient and stable nanocarriers for Fe(ii) nutritional delivery.