Food Source Categories
places, and bar, tavern, or lounge categories) and cafeterias (school and non-school). “Other” sources for purposes of this analysis represent an average of 22 percent of the daily sodium in 2003–2006 and include sources such as child care centers, vending machines, street vendors, sports events, and community food programs.
The data used to characterize sodium intake by contributing source are largely obtained from self-reported intake surveys coded using composition databases. As such, they are subject to the same limitations described for estimating intake by self-report. As discussed earlier, the constantly evolving food supply and increasing globalization make it a challenge to maintain updated food composition databases or databases for supplements that may also undergo formulation changes. Furthermore, new technologies for analyzing samples may change established values for the nutrient content of certain foods. Each food item listed in self-reported intake surveys has a code that corresponds to an entry in the database. However, foods may not have unique food codes; they are often grouped with similar foods within a food group and assigned an aggregate nutrient content based on the market share of the items in the food code.
The categorization of foods in the database can affect the ability to track the contribution of individual food items to sodium intake over time. How researchers decide to categorize and report foods can also have a major influence on the rank ordering of which foods are the greatest contributors to sodium intake and can make data comparisons across studies difficult (Cole and Fox, 2008; Cotton et al., 2004; Subar et al., 1998).