2008 Annual Report 1a.Objectives (from AD-416) This research focuses on integrating soil, agronomic, physiological and nutritional research to provide criteria needed to design cultural practices and allow genetic modifications of staple food crops to improve human health. It will lead to the development of sustainable ways to improve the nutritional quality and safety of principal plant foods with respect to micronutrient elements (e.g., Fe and Zn), certain vitamins and heavy metals (e.g., Cd) that are considered to be significant human health problems. These objectives will be achieved through research directed at obtaining a better understand of the chemistry and availability of these elements in soil, their spatial distribution and variability in areas of crop production, their absorption by roots, their translocation to and deposition in edible portions of food crops, the identification of selection criteria for identifying genetic factors involved in controlling their accumulation by plants, and identifying food substances that effect their bioavailability to humans from typical diets and their mechanisms of action in the gut. 1b.Approach (from AD-416) Effects of soil chemical and physical factors (e.g., elemental form, salinity, landscape position) on availability of important health-related elements (e.g., Fe, Zn, Cu, Se, Cd, etc.) to crops and their accumulation in human foods will be studied. Cereal genotypes will be studied for differences in grain-Cd accumulation and interactions with Zn fertilizers to improve food safety. Mechanisms of micronutrient homeostasis will be studied in whole plants and reproductive organs to improve their density and bioavailability in edible products. Genetic modifications will be used to increase health-promoting substances in food crops and to identify important plant food inhibitors (e.g., certain polyphenols) of Fe and Zn bioavailability to humans. In vitro or animal models will be used to study enteric bioavailability of important nutrients, and examine mechanisms of action of promoter and inhibitor substances in human diets. An in vitro Caco-2 cell model will be modified to study interactions of diet with nutrient bioavailability (e.g., Fe, Zn, provitamin A carotenoids), test the role of hind-gut microorganisms on nutrient absorption from foods, and assess the role of non-digestible carbohydrates (e.g., inulin) in this process. 3.Progress Report Improving the nutritional quality of staple food crops for Fe and Zn bioavailability, and defining the roles of prebiotics, beneficial bacteria and polyphenolic compounds is directly relevant to the Action Plan for Program 107, specifically Performance Measure 5.2.2 (“Define the role of nutrients, foods,…), Problem Statement 1D (“Enhance the Health-Promoting Quality of the Food Supply”). This research should improve the food supply by pursuing plant breeding strategy and molecular genetic approaches to enhance the nutritional quality of a major staple food crop. In addition, defining the roles of the major plant food components that are known to have health benefits will also serve the Action Plan. More progress has been made in identifying molecular markers that correlate with grain-Fe concentration and bioavailability using recombinant inbred lines of maize. This work has promising implications for plant breeders seeking to develop maize varieties that are higher in bioavailable Fe. Progress was also made in quantifying the effect of the environment and the interaction of the environment and genotype on Fe bioavailability and concentration. Fe biofortified and common black bean genotypes obtained from the Center for International Tropical Agriculture (CIAT) in Cali Colombia were evaluated for Fe bioavailability using a piglet model. The results of this study showed that the high-Fe black bean genotype provided significantly more bioavailable Fe to piglets compared to a common lower Fe black bean genotype even though both bean genotypes contain significant levels of antinutrients (i.e., polyphenolics and phytate). Human studies are being planned to advance this research. Iron concentration and Fe bioavailability were measured in select varieties of potatoes. Research indicates that certain genotypes known as “phurejas” have more bioavailable Fe relative to commercial varieties. Additional research is underway to determine consistency of the lines for improved bioavailability and higher Fe concentration. Studies to develop an intestinal loop model using poultry were initiated. This model will be useful to evaluate foods for Fe bioavailability and other nutrients. It may have significant advantages in terms of cost, versatility and the amount of experimental samples needed. Analytically, an ultra high pressure liquid chromatography (UPLC) method was developed for amino acid analyses that reduce sample run times from 45 min to 10 minutes greatly improving sample throughput efficiency. Further, an ion chromatography method was developed for nicotianamine (a non-protein amino acid involved in intra and intercellular trace metal movement in plant tissues and organs) determination in plant tissues which is being applied in research directed at transferring more Fe from vegetative tissues into seeds and to improve Fe bioavailability from seeds to humans. 4.Accomplishments 1. Biofortified high-Fe black beans improve Fe status of Fe-depleted piglets compared to standard black beans with normal Fe levels. Iron deficiency is the leading human nutritional deficiency worldwide. Improving the bioavailable amounts of Fe in staple food crops would contribute to a reduction in Fe deficiencies globally. Biofortified high-iron (Fe) black beans were shown to be better sources of Fe compared to black beans not biofortified using a piglet model. Beans are high in phytate and polyphenols, known inhibitors of Fe absorption, and this research demonstrates that the adaptive capabilities of the intestinal tract can overcome the negative effects of iron inhibitors in bean seeds. Thus, biofortifying beans with Fe may be a viable strategy for addressing Fe deficiency in target populations at risk of developing Fe deficiency and dependent on beans for their. This accomplishment addresses Component 1, Problem Statement 1D and Component 2, Problem Statement 2A of National Program 107. 2. Iron-biofortified potatoes may provide substantial amounts of iron (Fe) to Fe deficient individuals. Iron deficiency is the leading nutritional deficiency worldwide. A major cause of iron deficiency is low bioavailable Fe in the diet. Numerous in vitro studies were conducted showing that potatoes are excellent source of Fe as they lack a major inhibitor of Fe absorption, phytic acid, can contain significant levels of a promoter of Fe absorption (i.e., ascorbic acid) and can contain significant amounts of bioavailable Fe. Biofortifying potatoes with higher levels of iron may help reduce iron deficiency in people dependent on potatoes for their sustenance. This accomplishment addresses Component 1, Problem Statement 1D and Component 2, Problem Statement 2A of National Program 107. 3. Both red and white beans are good sources of bioavailable iron (Fe) and zinc (Zn). Deficiencies of Fe and Zn afflict over 20% of the world’s population especially resource-poor children in the Global South. A piglet model was used to test the bioavailability of Fe and Zn in red and white beans intrinsically labeled with stable isotopes of Fe and Zn. Red bean seed coats contained high levels of polyphenols that can inhibit Fe absorption from the intestine while white beans contained none. Isotope ratios in whole blood and plasma samples were used to calculate Fe and Zn absorption, respectively from the bean meals. Fe absorption was high from both bean sources averaging about 15%. Zn absorption was also high averaging about 33% from both bean types. Thus, both red and white beans are good source of absorbable Fe and Zn even though red beans can contain high levels of polyphenols. Biofortifying beans with Fe and Zn may provide significant levels of utilizable Fe and Zn to target populations helping reduce deficiencies of these nutrients globally. This accomplishment addresses Component 1, Problem Statement 1D and Component 2, Problem Statement 2A of National Program 107. 5.Significant Activities that Support Special Target Populations None. 6.Technology Transfer Number of Non-Peer Reviewed Presentations and Proceedings 3 Number of Newspaper Articles and Other Presentations for Non-Science Audiences 1 Review Publications Yasuda, K., Maiorano, R., Welch, R.M., Miller, D., Lei, X. 2007. Cecum is the major degradation stie of ingested inulin. Journal of Nutrition. 137:399-2404. Jin, F., Welch, R.M., Glahn, R.P. 2006. Moving toward a more physiological model: application of mucin to refine the in vitro digestion/Caco-2 cell culture system. Journal of Agricultural and Food Chemistry. 54:8962-8967. Ariza-Nieto, M., Blair, M., Welch, R.M., Glahn, R.P. 2007. Screening of iron bioavailability patterns in eight bean (Phaseolus vulgaris L.) genotypes using the Caco-2 cell in vitro model. Journal of Agricultural and Food Chemistry. 55:7950-7956. Beisiegel, J.M., Hunt, J.R., Glahn, R.P., Welch, R.M., Menkir, A., Maziya-Dixon, B.B. 2007. Iron bioavailability from maize and beans: a comparison of human measurements with Caco-2 cell and algorithm predictions. American Journal of Clinical Nutrition. 86:388-396.