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Children's Nutrition Research Center

Houston, Texas

Children's Nutrition Research Center - CNRC
USDA/ARS Children's Nutrition Research Center
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Research - Absorption And Metabolism Of Essential Mineral Nutrients In Children

Mineral Absorption and Metabolism in Children

Steve Abrams, Paz Etcheverry

The goal of our research is to provide data to enhance the development of nutritional guidelines, especially as related to mineral nutrition, in children. Using both human experimentation and cell culture models, we are studying methods of delivering the key minerals of calcium, zinc and iron in the diet so as to optimize health outcomes. This is done by evaluating enhancers of mineral absorption, such as ascorbic acid, prebiotic fibers and vitamin D and by considering nutrient: nutrient interactions that may limit mineral absorption such as an excess in the zinc: copper intake ratio. We will conduct a controlled trial of vitamin D supplementation to assess the effects of vitamin D status on calcium absorption in small children. We will evaluate different types of whole diets (lacto-ovo vegetarian) on iron status and the effects of differing intakes of zinc on zinc and copper absorption. We will determine if benefits previously seen for prebiotic fibers in enhancing calcium absorption also occur for iron absorption. These studies will utilize stable isotope techniques so as to provide accurate, practically applicable information which may be obtained from the study populations in a safe manner. In vitro studies will seek to identify genetic basis for mineral absorption and to develop appropriate models for evaluation of mineral absorption. Taken together, this project will provide novel information directly useful to government, industry and the consumer related to dietary requirements. These data will have global application and provide a strong basis for evidence-based nutritional recommendations to be developed.

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Modifying Plant Transport Processes for Enhanced Nutritional Quality of Plant Foods

Michael A. Grusak, Kendal D. Hirschi, Paul Nakata

The long-term objective of this project is to contribute to the development of nutritionally enhanced plant foods and to develop tools for testing nutrient bioavailability. We have chosen to work initially with plants that are tractable molecular genetic systems (Arabidopsis, Medicago, and soybean) where we can perform gene discovery quickly. We then translate these findings into agriculturally important crops that can be easily transformed and for which established protocols are in place for measuring nutrient absorption in both mice and humans. Specifically, we will work to identify and characterize genes and gene products that are involved in mineral transport throughout the plant, focusing both on whole organ accumulation and subcellular partitioning of minerals. We also will identify and characterize the molecular processes associated with calcium oxalate formation in plants. We envision this work to eventually have relevance to mineral nutrition improvement (e.g., calcium, magnesium, iron, and zinc) in several agronomic crops. In addition, we will develop new, cost-effective methods for the intrinsic labeling of plant foods, using stable isotopes, in order to facilitate nutrient bioavailability studies in humans. These efforts will expand our capabilities for assessing the absorption and metabolism of various plant-derived minerals and phytochemicals. They also will facilitate the generation of new bioavailability data for various nutrients, which will allow informed decisions when policymakers establish future dietary recommendations for humans.

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