Oat protein nanofibril-iron hybrids as a stable, high-absorption iron delivery platform for human nutrition

Iron deficiency and anemia are significant global health issues, affecting nearly two billion people worldwide. The World Health Organization recommends iron fortification of foods as an effective strategy to reduce anemia rates. Available iron fortificants, however, are limited by low absorption and/or poor sensory performance. Developing new iron compounds that deliver highly bioavailable ferrous iron in foods without compromising sensory quality remains a challenge. In this work, we introduce oat protein nanofibrils (OatNF) carrying ultrasmall iron nanoparticles as promising iron fortificants for foods and beverages. Tailored synthesis of OatNF hybrids can produce iron nanoparticles in either the ferrous or ferric state. When sodium ascorbate (SA) is used as the reducing agent, the OatNF carry stabilized ferrous iron which is remarkably well absorbed in humans. In iron-deficient women, geometric mean absorption is found to be 46.2% (95% CI: 39.1%-54.7%) when given with water and 13.4% (95% CI: 9.8%-18.3%) when given with a polyphenol-rich food, representing 76% and 66% higher absorption, respectively, than the reference compound, FeSO4. When NaOH is used as the reducing agent, the OatNF carry mainly ferric iron, which is well-absorbed and shows superior sensory performance in reactive food matrices. These promising results introduce OatNF hybrids as a possible cost-effective, plant-based and organoleptic-friendly solution to the global challenge of iron deficiency anemia.