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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Nutrient Data Laboratory » Research » Research Project #432268

Research Project: Development of USDA Special Interest Database on Iodine in US Foods

Location: Nutrient Data Laboratory

Project Number: 8040-52000-064-42-I
Project Type: Interagency Reimbursable Agreement

Start Date: Oct 1, 2016
End Date: Sep 30, 2018

The purpose of this collaboration is to develop a Special Interest Database in iodine content of foods extending work already done on dietary supplements, focusing on major contributors of iodine in the current United States food supply. This will require laboratory analysis of selected foods. Such foods can be either those with high level of iodine, or possibly any foods for which consumption levels are high (based on NDL 5-year Strategic Research Plan, currently under review) even if iodine levels are modest (since contribution to total intake might be considerable). food supply, such as regarding commercially processed foods or commodity foods that have changed (e.g., meats). Data are also needed on the content of various bioactive compounds in foods, and on certain trace minerals (e.g., iodine), for which little or no food composition data exist.

NFNAP study foods that are likely to contain measurable amounts of iodine will be selected for the initial portion of the proposed new study including archived samples from previous years. This selection will be based on the Food and Drug Administration (FDA), 2013 Total Diet Study (TDS) database of iodine content of the market basket food. They will be sent along with quality control materials to a commercial laboratory, to Covance or another qualified laboratory, for analysis. In addition to the existing NFNAP foods, other foods may be selected and obtained under the NFNAP program if they are likely to be a significant sources of iodine. A combined list of existing data from USDA and FDA (from Total Diet Study 2011, 2012 and 2013) has been used to make key food calculations for individual foods (Appendix 1); consumption and concentration data are used to identify priorities. From this, proposed foods for future analysis would include: • expanded seafood products (especially finfish) • seaweed and seaweed extracts as ingredients • other iodine-containing commercial ingredients or additives • highly consumed commercially processed mixed dishes (especially those containing dairy and/or egg products) • retail salt products • home prepared recipes using iodized versus non-iodized salt • other foods determined to have significant amounts of iodine It should be noted that, using current data, four dairy and egg products contribute to two thirds of the national intake of iodine. Likely due to environmental exposure or supplements, extensive sampling and analysis of these and related products would be appropriate – variability information is vital to research. As part of the 2013 Interagency Roundtable on Iodine Research, FDA and USDA committed to advancing jointly on development of iodine data in public. The initial products were AJCN supplement publications outlining a strategy on sampling and analysis. The variability of iodine in foods was addressed as part of these meetings and to move forward, sampling and analysis should be sufficient to allow for determination of variability estimates in addition to means in targeted foods. The budget below addresses multiple samples/food. The salt industry should be engaged to provide data exploring the degree to which iodized salt loses iodine through volatilization over time in households and other establishments, under varying storage, humidity and temperature conditions. In addition, information on sales of iodized and non-iodized salt should be obtained.