A Stable Isotope Study in Young Iron-depleted Thai Women to Evaluate the Bioavailability of an Oat Protein-based Iron Delivery System

Iron (Fe) deficiency is the most common nutrient deficiency present worldwide. Alternative solutions are needed for better absorption due to drawbacks that are associated with gastrointestinal side effects from Fe salt supplements. Additionally, Fe is difficult to add as a fortificant to foods due to the organoleptic changes that it causes. Reducing the particle size of iron salts improves their absorption, and submicron-sized Fe compounds are a promising solution in food matrices, although their tendency to oxidize and rapidly aggregate in solution limits their use in fortification.

A novel β-lactoglobulin (BLG) fibrils-Fe compound for use in Fe fortification was developed from milk proteins, and its evaluation in both in vitro digestion and in vivo (rat) bioavailability studies has been reported. It was observed that the material's reducing effect, colloidal stability, improved sensory performance and high bioavailability, making it promising for nutritional applications.

In the current study, a similar strategy is used to isolate amyloid fibrils from a vegan and more sustainable source, namely, oat protein. The reducing ability of the amyloid fibrils on the Fe salt - FeCl3 in the presence of sodium ascorbate (SA) or sodium hydroxide (NaOH), both food grade reagents, has shown the formation of a mixture of Fe2+ and Fe3+ particles with no observed aggregation. A previous human study showed that Fe3+ ions from submicron-sized ferric phosphate had a similar fractional Fe absorption (FIA) compared to that of ferrous sulfate (FeSO4), the current standard of care. The amyloid fibril systems by milk protein as efficient carriers for iron fortification. The evaluation in vitro digestion and in vivo bioavailability showed that β-lactoglobulin (β-lg) fibrils by milk protein disappeared 4 hours after providing this amyloid-rich supplement in the intestinal tract immediately. Moreover, the brain section of the mice supplemented with β-lg amyloid fibril showed no amyloid plague after 1 month of feeding. The β-lactoglobulin (β- lg) fibrils and plant-based oat share the same structure in the amyloid by milk protein. From these results, fibrils by oat are understood to be safe for nutrition.

Additionally, a recent study showed the possibility to produce amyloid fibrils from oat in full analogy to those obtained by BLG. In the current study, the OAT fibril - Fe SA (Fe-oat 1) and OAT fibril - Fe NaOH (Fe-oat 2) will both be studied in vivo, alone are oat fibril powder add iron supplement is soluble in water and oat fibril powder add iron supplement is soluble in water in a food matrix (acai puree and honey) to assess their promise as Fe food fortificants.

This first in human study to short-term food safety assessment and adverse effect of the OAT fibril - Fe SA (Fe-oat 1), OAT fibril - Fe NaOH (Fe-oat 2) and in a food matrix to assess their promise as Fe food fortificants.