Progress 05/01/04 to 03/31/09
Outputs
Progress Report Objectives (from AD-416) To utilize in vitro and in vivo models of Fe and Zn bioavailability to screen select micronutrient-dense staple food crops (rice, wheat, maize, beans, sweet potato, and cassava) and identify those varieties that have high Fe and Zn bioavailability. In addition, these models will be used to investigate diet and food ingredient interactions that influence bioavailability of these minerals. Approach (from AD-416) We propose to use a two-tiered approach in the evaluation of the bioavailability of Fe and Zn in select micronutrient-dense staple plant food genotypes under development in this project. First, we will employ the in vitro Caco-2 cell model to screen large numbers of promising micronutrient-dense genotypes of staple plant food crops for bioavailable Fe. Then, after using this approach to identify promising, Fe-enriched genotypes, we will employ a pig model to evaluate both Fe and Zn bioavailability in each select genotype in the context of whole diets typical of each reference region of the project. Samples that show promise in this collaborative research can then be advanced for human trials with other collaborators of the Harvest Plus program. Significant Activities that Support Special Target Populations In FY 2009, this project received no funding in the past year and terminated on 3/31/2009; hence, there is no progress to report.
Impacts
(N/A)
Publications
|
Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) To utilize in vitro and in vivo models of Fe and Zn bioavailability to screen select micronutrient-dense staple food crops (rice, wheat, maize, beans, sweet potato, and cassava) and identify those varieties that have high Fe and Zn bioavailability. In addition, these models will be used to investigate diet and food ingredient interactions that influence bioavailability of these minerals. Approach (from AD-416) We propose to use a two-tiered approach in the evaluation of the bioavailability of Fe and Zn in select micronutrient-dense staple plant food genotypes under development in this project. First, we will employ the in vitro Caco-2 cell model to screen large numbers of promising micronutrient-dense genotypes of staple plant food crops for bioavailable Fe. Then, after using this approach to identify promising, Fe-enriched genotypes, we will employ a pig model to evaluate both Fe and Zn bioavailability in each select genotype in the context of whole diets typical of each reference region of the project. Samples that show promise in this collaborative research can then be advanced for human trials with other collaborators of the Harvest Plus program. Significant Activities that Support Special Target Populations 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.� To monitor progress on this project, frequent meetings, emails and telephone conversations were used. Studies conducted to determine the adequacy of extrinsic radiolabeling of bean Fe, indicated that extrinsic radiolabels did not equilibrate completely with the intrinsic Fe in the bean. This observation implies that the more costly method of intrinsic isotope labeling of bean Fe is needed to accurately evaluate Fe bioavailability from beans. The bioavailability of Fe in the ferritin form was evaluated in a simulated digestion/cell culture model and found not to be a form of Fe with enhanced bioavailability. Ferritin was degraded in the acid pH of the stomach and digestive enzymes thus releasing iron from ferritin in the inorganic form. Legume seeds store significant amounts of Fe as ferritin but the bioavailability of ferritin-Fe is in question. In agreement with human studies, in vitro studies demonstrated that ferritin Fe bioavailability is the same as FeSO4. In addition, ferritin-Fe is released during digestion at the low pH of the stomach contents and interacts with dietary Fe inhibitors and promoters similar to FeSO4. These results indicate that ferritin Fe is not a promoter of Fe bioavailability. Approximately 160 maize samples were received from collaborators at CIMMYT in Mexico. The objective was to determine the degree that genotype by environment interaction affect Fe bioavailability. It is important to know relative effects of this interaction on this nutritional trait as it may overwhelm the effect that can be introduced by genotype alone. Cassava samples were also received from the International Institute of Tropical Agriculture (IITA) and from CIAT and evaluated for Fe concentration and bioavailability. IITA samples were not high in Fe concentration and did not show a diverse range of Fe concentration and bioavailability. CIAT samples appeared to be higher in Fe and have more bioavailable Fe.
Impacts
(N/A)
Publications
|
Progress 10/01/05 to 09/30/06
Outputs
Progress 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.
Impacts
(N/A)
Publications
|
Progress 10/01/04 to 09/30/05
Outputs
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 have been initiated 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 the Department of Food Science and the Department of 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. Studies are also under way to compare 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.
Impacts
(N/A)
Publications
|
Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? D. 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 entitled "Bioavailability of Fe and Zn in Biofortified Crops". 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." The commercial GOYA bean lines studied were chosen for use in a pilot study to test for the effect of inhibitory compounds in bean seed hulls on Fe bioavailability using an in vitro Caco-2 cell model. These studies suggest that the Fe uptake inhibitory compounds may be related to seed coat color possibly associated with certain polyphenolic compounds in the hull. Interestingly, the removal of the hull from the white bean decreased Caco-2 ferritin formation, indicating
the possible presence of an Fe uptake promoter in the white hull. Overall, these experiments indicate that whole colored beans contain Fe absorption inhibitors in the hulls that are little affected by the addition of the Fe bioavailability promoter substance, ascorbic acid. Comparison of Fe bioavailability in 19 genotypes of Columbian bean samples indicated that all bean genotypes tested contain very little bioavailable Fe. This result reaffirmed the association of bean color with very low Fe bioavailability. Nevertheless, several varieties studied contained more bioavailable Fe than the others tested as indicated by their abilities to induce ferritin levels above the baseline of ferritin formation in cells. White beans genotypes had significantly more bioavailable Fe compared to the colored bean genotypes tested. This difference is not due to bean phytate levels but most likely the result of the presence of certain colored polyphenolic compounds in the hulls. Efforts to identify
and characterize the nature of these compounds should be vigorously pursued. Furthermore, further studies should investigate the possibility that white seed coats contain promoters of Fe bioavailability.
Impacts
(N/A)
Publications
|
|