2006 Annual Report 4d.Progress report. This report serves to document research conducted under a General Assistance Type Cooperative Agreement between ARS and the Department of Food Science at Cornell University. Additional details of research can be found in the report for the parent project 1907-42520-003-00D, "Understanding Soil-Plant-Human/Animal Food Systems and Nutrient Bioavailability to Improve Human Health." Experiments were performed to determine the bioavailability of iron in two wheat varieties that differ in their inulin levels (one high and one low inulin wheat variety) using a pig model in cooperation with Drs. Dennis Miller (Department of Food Science) and Xingen Lei (Dept. Animal Science) at Cornell University. Previous pig model studies, carried out in 2004 and early 2005, showed that pigs fed a maize-soy based diet supplemented with 4% inulin absorbed significantly more iron from the diet (as determined by iron incorporation into hemoglobin; hemoglobin repletion efficiency) compared to pigs fed the same diet not supplemented with inulin. Unfortunately, the wheat lines provided by our cooperators at the University of Adelaide, S. Australia were found to contain similar amounts of inulin and therefore, the experiment did not provide any useful information. Studies also compared iron bioavailability from colored and white beans fed to pigs with the same bean varieties screened for iron bioavailability using an in vitro Caco-2 cell model in order to further validate the Caco-2 cell model. Results showed significant differences between the models in the amount of bioavailable Fe in the beans lines studied. Further research is underway to ascertain the reason for these differences. This research was supported, in part from HarvestPlus funds.