Caco-2 Cell and Animal Model Studies (Gallus gallus) Are Effective at Screening and Developing Staple Food Crops with Improved Fe Bioavailability.

Background and objectives: Iron (Fe) biofortification is a strategy that alleviates Fe deficiency by improving Fe bioavailability and/ or concentrations in staple crops. In order to develop improved lines of staple food crops, breeders need a high throughput screening approach that accurately ranks bioavailability relative to standard reference controls. Molar ratios of known food factors such as phytic acid, polyphenols, and ascorbic acid are often highly linked to environmental and processing effects and thus not reflective of the genetics of Fe bioavailability. Methods: A bioassay such as the in vitro digestion/Caco-2 cell model is therefore necessary for measurement of Fe bioavailability during the crop development stage. This should follow by a subsequent animal studies that are useful and cost-effective to confirm the in vitro observations and advance select lines for human efficacy studies. Results: Our research team has conducted several studies aimed to screen Fe bioavailability in different crops using our in vitro (Caco-2) and in vivo (Gallus gallus) models. In these studies, we implement physiological, cellular and molecular parameters in order to accurately measure the dietary Fe bioavailability in the tested crops (including beans, pearl millet and wheat). Furthermore, this strategy has identified possible Fe bioavailability QTL in bean cotyledons, and has found seed coat polyphenols to be major inhibitors of bean Fe absorption. Conclusions: Differences identified by these models in crops such as pearl millet, lentils and beans indicate that plant breeding can significantly improve Fe bioavailability in these crops. In addition, these screening tools also have the capacity to cost-effectively monitor Fe biofortified crops once they are released to farmers and dispersed into the food system. Such monitoring will likely be needed to ensure the biofortification effect.