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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Plant, Soil and Nutrition Research » Research » Research Project #426380

Research Project: Bioavailability of Iron, Zinc and Select Phytochemicals for Improved Health

Location: Plant, Soil and Nutrition Research

2016 Annual Report

1. In collaboration with international teams of plant breeders, we will develop lines of staple food crops such as beans, pearl millet, sorghum, rice, lentils and maize with improved Fe and Zn content and bioavailability. 1.A. Identify molecular markers and ultimately the genes that influence iron level and bioavailability in maize seed. Quantitative trait loci (QTL) mapping and an in-vitro digestion/Caco-2 cell culture model system will be used for this research sub-objective. 1.B. Identify molecular markers and ultimately the genes that influence iron level and bioavailability in lentils. Quantitative trait loci (QTL) mapping and an in-vitro digestion/Caco-2 cell culture model system will be used for this research sub-objective. 1.C. Identify agricultural and processing practices that enhance the nutritional quality of Fe in staple food crops. 1.D. Continue our work to identify compounds that promote or inhibit Fe bioavailability in staple food crops. 2. Evaluate a surgical duodenal loop model in poultry as a tool to measure bioavailability of health promoting phytochemicals. 2.A. Determine if absorption of selected phytochemicals can be measured in the poultry duodenal loop model. 2.B. Define bioavailability of specific phytochemicals from select foods using the validated duodenal loop model.

This project has two major objectives. The first is to develop lines of staple food crops with improved bioavailability and content of iron (Fe). To do so we will employ our established screening tools of an iron bioavailability bioassay and an animal model. In conjunction with these tools, we will make use of mass spectroscopy and marker assisted molecular breeding techniques. With these approaches, we will be able to identify and utilize regions of the plant genome that harbor genes associated with the enhanced food crop nutritional quality for Fe. To further complement the above approaches, we will continue our work on the identification of agricultural and food processing practices that enhance the bioavailability and content of Fe and Zn in staple food crops. The second major objective of this project is to develop a method to measure and evaluate the bioavailability of functional phytochemicals from plant foods. To do so, we will assess the use of a surgical model utilizing the unique intestinal anatomy of the broiler chicken to measure absorption of compounds from the duodenal segment of the intestine. This approach uses an established surgical preparation involving anesthetized animals. Our initial efforts with this model will focus on compounds that are common to many staple food crops, fruits and vegetables. These phytochemicals will include the flavonoids epicatechin, quercitin, caffeic acid, chlorogenic acid and kaempferol. Enhancing our knowledge of bioavailability of health promoting phytochemicals will significantly improve efforts to develop more nutritious plant foods.

Progress Report
The loss of our in-house collaborating maize breeder in fiscal year 2014 resulted in a 5-7 year setback in our maize research of Objective 1; however, with the establishment of a collaborating maize breeder at Purdue University we now have potential genetic markers for maize Fe content and expect potential markers for maize Fe bioavailability in the near future. The inability of collaborators at the University of Saskatchewan to produce additional mapping populations of lentils has also been disappointing. In contrast, in collaboration with a bean breeder at Michigan State University, we have determined that faster cooking time in beans is related to improved Fe bioavailability. Also, in this collaboration we have developed a “Health and Nutrition Panel” of beans that encompasses (4) market classes and (3) levels of cooking time for each market class. This panel enables further study of Fe bioavailability and cooking that can have significant domestic and international benefits for growers and consumers. Also from this work, we are developing varieties in the yellow market class of beans that show a 30-50% reduction in cooking time, high bioavailable Fe and strong consumer preference. Specific polyphenol profiles in bean market classes show that these promising yellow bean lines contain mostly promoters of Fe bioavailability and reduced levels of inhibitory polyphenols. Moreover, the yellow beans represent an emerging popular market class in the U.S. and are highly desired in many parts of Africa. In addition to the above, the bean cotyledon cell wall was identified as a potential new major factor that inhibits iron absorption from beans and possibly other legumes. This discovery could redirect bean breeding and also significantly revise and improve our knowledge of bean Fe absorption and bioavailability. As resources have not allowed equipment purchases for pursuit of Objective 2 of this project plan, we have substituted an alternative approach that is within our resources, using an “in ovo” feeding model to address the effects of specific phytochemicals (g. daidzein, obipectin) on intestinal transport enzyme functionality and prebiotic potential.

1. Identification of the bean cotyledon cell wall and the intracellular matrix as major factors affecting bean iron bioavailability. Approximately 80% of the Fe in beans is sequestered within the cotyledon cells of beans in a protein and phytic acid rich matrix. We have demonstrated that cotyledon cell walls are not broken down via cooking and are highly resistant to digestion in the upper intestine which is the major site of Fe absorption. A major portion of bean Fe is thus unavailable for absorption until the latter part of the small intestine when intestinal microbes initiate break down of the cotyledon cell walls and facilitate release of the intracellular Fe; however, at this point in the intestine, Fe absorption capabilities are much lower. Moreover, in some varieties of the beans, the intracellular matrix where the Fe is stored also prevents release of the Fe for absorption. This finding requires us to rethink our knowledge of how Fe may be absorbed from beans and possibly other legumes, and may redirect bean breeding and food processing strategies to improve beans as a source of Fe.

2. Development of the “Health and Nutritional Panel” of beans to demonstrate nutritional benefits of bean consumption. In collaboration with ARS scientists at Michigan State University, we have developed a “Health and Nutrition Panel” of beans that demonstrates the enhanced nutritional benefits of fast cooking bean lines. Nutritional studies have shown that Americans would maintain better control of weight and health by consuming more pulse crops such as beans; however, one of the factors that discourages bean consumption is cooking time. Cooking time is also one of the major factors that prevents more bean consumption internationally, such as in sub-Saharan Africa where most households use wood or charcoal for cooking. Thus, longer cook beans create more household expense for fuel and effectively reduce bean consumption. The Health and Nutrition Panel was refined and selected from the Andean Diversity Panel, a major library of bean varieties used by bean breeders. In refining the selection and creating this panel, we summarize and present to consumers and bean growers a strategy that promotes more bean consumption and demonstrates the nutritional benefit of staple food crop.


Review Publications
Trijatmiko, K.R., Duenas, C., Torrizo, L., Oliva, N., Francisco, P., Mae Arines, F., Adeva, C., Balindong, J., Sapasap, V., Barry, G., Slamet-Loedin, I.H., Lombi, E., Stangoulis, J., Johnson, A., Tako, E.N., Glahn, R.P. 2016. Biofortified indica rice attains iron and zinc nutrition dietary targets in the field. Scientific Reports. 6:19792.
Reed, S.M., Neuman, H., Moskovitch, S., Glahn, R.P., Koren, O., Tako, E.N. 2015. Chronic zinc deficiency alters chick gut microbiota composition and function. Nutrients. 7:1-17.
Della Valle, D.M., Glahn, R.P., Shaff, J., O'Brien, K.O. 2015. Iron absorption from intrinsically-labeled lentils. Journal of Nutrition. DOI: 10.3945/jn.115.217273.
Tako, E.N., Reed, S.M., Anandaraman, A., Hart, J.J., Beebe, S.E., Glahn, R.P. 2015. Studies of cream seeded carioca beans (phaseolus vulgaris L.) from a Rwandan efficacy trial: in vitro and in vivo screening tools reflect human studies and predict beneficial results from iron biofortified beans. PLoS One. DOI: 10.1371/journal.pone.0138479.