Iron bioavailability from multiple biofortified foods using an in vitro digestion, Caco-2 assay for optimizing a cyclical menu for a randomized efficacy trial (P10-029-19)

Authors: GANNON, BRYAN - Cornell University; Glahn, Raymond; MEHTA, SAURABH - Cornell University

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2018
Publication Date: 6/13/2019
Citation: Gannon, B., Glahn, R.P., Mehta, S. 2019. Iron bioavailability from multiple biofortified foods using an in vitro digestion, Caco-2 assay for optimizing a cyclical menu for a randomized efficacy trial (P10-029-19). Current Developments in Nutrition. 3(1). https://doi.org/10.1093/cdn/nzz034.P10-029-19.
DOI: https://doi.org/10.1093/cdn/nzz034.P10-029-19

Interpretive Summary: A multiple biofortified food crop trial targeting iron (Fe), zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is being conducted in India. We sought to determine the relative iron bioavailability from biofortified and conventional crops and crop combinations representative of a cyclic menu using crops targeted for inclusion in the feeding trial. Crops were procured from India, cooked, freeze-dried, and analyzed with an established cell culture assay for Fe nutrition. High Fe pearl millet alone demonstrated higher iron uptake than conventional varieties. Addition of sweet potato or sweet potato + lentil improved iron uptake for all proportions tested in control varieties and select proportions for biofortified varieties. Two multiple crop combinations demonstrated modestly higher iron uptake from biofortified crops. Food matrix effects, processing, and promoters/inhibitors of iron absorption should be considered in addition to total iron concentration when optimizing iron delivery from biofortified crops. This study enables nutritionists conducting the human trial to optimize the study design for greater chance of success at delivering more absorbable Fe.

Technical Abstract: A multiple biofortified food crop trial targeting iron, zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is being conducted in India. We sought to determine the relative iron bioavailability from biofortified and conventional crops and crop combinations representative of a cyclic menu using crops targeted for inclusion in the feeding trial. Crops were procured from India, cooked, freeze-dried, and analyzed with an established in vitro digestion/Caco-2 iron bioavailability assay using a fixed sample weight. Representative crop proportions were determined using k-means clustering and combined such that samples included either all biofortified or all control crops. The primary outcome was iron uptake measured by Caco-2 ferritin production normalized to total Caco-2 protein (ng ferritin / mg cell protein). Biofortified pearl millet alone demonstrated higher iron uptake than conventional varieties (5.01±1.66 vs. 2.17±0.96, P = 0.036). Addition of sweet potato or sweet potato + pulse improved iron uptake for all proportions tested in control varieties and select proportions for biofortified varieties (P = 0.05). Two multiple crop combinations demonstrated modestly higher iron uptake from biofortified crops. Cell ferritin normalized to iron per sample was higher for control crops, and enhanced by sweet potato and lentil. Matrix effects, processing, and promoters/inhibitors of iron absorption should be considered in addition to total iron concentration when optimizing total iron biodelivery. Future directions include evaluating recipes as prepared for consumption and validation against human iron bioavailability studies.