Phosphorus bio-accessibility measured in four infant formulas using in vitro batch digestion translates well into phosphorus bio-availability in mice

Abstract Objective To quantify the bio-accessibility of phosphorus (P) from amino acid-based formulas (AAFs) under different digestive conditions. Methods We developed in vitro batch digestion models with stomach digestion at different pH mimicking normal digestive condition and conditions representing use of acid suppressive medication. To validate bio-accessibility findings we devised a low P murine model to test P bio-availability under compromised digestive conditions using proton pump inhibitors (PPI) to neutralize stomach pH. Results In vitro P bio-accessibility of AAFs Neocate® Infant and Neocate® Junior ranged between 57% and 65% under normal digestive conditions for infants (stomach pH 3.5) and between 38% and 46% under conditions that simulate bypass of stomach acidification, which is comparable to control diet and two EleCare® AAFs. In vivo bioavailability analysis showed that both Neocate® formulas were able to normalize plasma P levels when administered to low P mice along with PPI (control diet+PPI 8.0±0.4, Neocate® Infant 10.1±0.9, Neocate® Junior 9.2±0.6, EleCare® Infant 8.6±0.4, EleCare® Junior 8.7±0.5, n=8-10, p Conclusion Our findings indicate that P bio-accessibility in the in vitro batch digestion model translates well into P bio-availability in mice even under compromised digestive conditions that bypass gastric acidification.