Fibrous and Amorphous Antarctic Krill Protein Aggregates for Iron Delivery: High Efficacy and Low Gastric Irritation in Iron Deficiency Anemia.

Iron deficiency remains a critical global nutritional challenge, and food iron fortification is the primary intervention strategy for alleviating iron deficiency anemia (IDA). In this study, iron complexes based on fibrous aggregates (FA-Fe) and amorphous aggregates (AA-Fe) of Antarctic Krill protein were fabricated to investigate their structure-activity relationships and iron supplementation efficacy. Both complexes coordinated Fe2+ via carboxyl and amino groups, with FA-Fe exhibiting higher iron chelation capacity and structure-dependent functional divergence. In vitro digestion revealed sustained gastric release of FA-Fe, resulting in higher intestinal soluble iron content (19.05%) and bioaccessibility than AA-Fe and FeSO4. In the IDA model, FA-Fe restored hemoglobin, tissue iron stores, and iron homeostasis-related gene expression while mitigating gastric inflammation and oxidative stress, demonstrating superior biocompatibility. Thus, FA-Fe combines high efficacy with low gastrointestinal irritation, positioning structurally diverse Antarctic Krill protein aggregates as promising iron supplement carriers.