[Development of a new method for assessing the availability of low-sodium foods in Japan]

Objectives　Food environment improvement involving salt reduction requires improving access to and labeling low-sodium foods. Assessing the implementation status of these measures is also necessary. However, to date, no established methods exist for assessing the availability of low-sodium foods in communities. In this study, we aimed to devise a survey on the availability of low-sodium foods as a community food environment assessment method in order to establish common assessment methods, criteria, and practical measures, as well as standardization nationwide.Methods　A preliminary survey on the availability of low-sodium foods was conducted in Kitakyushu City in four stores with nationwide representation. Consent for providing information on handled product lists was obtained. The on-site lists collected through direct investigation by surveyors were compared with the handled product lists provided by the stores and analyzed to identify survey challenges and examine feasibility and the potential for accuracy. The definition of low-sodium foods, which emerged as a challenge in the preliminary survey, was confirmed. Preliminary survey data were carefully reviewed to establish classification criteria for low-sodium foods and create a low-sodium food list to serve as a reference for on-site surveys. Forms for recording the results of on-site surveys and a survey manual were developed. Registered dietitians conducted on-site surveys using the manual to confirm its applicability.Results　The preliminary survey results revealed that the on-site lists had fewer omissions and greater feasibility than store-provided lists. After clearly defining low-sodium foods, we established classification criteria (three major categories, seven subcategories, and 37 minor categories) considering the ease of on-site investigations and purchases. Three forms for recording survey results were developed, including a standard input form allowing detailed documentation of the availability of individual low-sodium foods, an aggregation form for a quantitative assessment of low-sodium foods availability, and a display form visualizing the availability of low-sodium foods by store. Furthermore, a survey manual was developed explaining the purpose and approach of the low-sodium foods availability survey, definition and classification criteria for low-sodium foods, and the three forms for recording survey results. Findings indicated that all registered dietitians could conduct on-site surveys using the manual and successfully collect and organize data.Conclusion　On-site surveys using the manual and documentation forms enabled easy and accurate assessments of low-sodium foods availability. Thus, this standardized method to assess the availability of low-sodium foods could be a food environment assessment method for regional salt reduction initiatives.