A systematic review of automated electronic supermarket sales data for population dietary surveillance.

CONTEXT: Most dietary assessment methods are limited by self-report biases, how long they take for participants to complete, and cost of time for dieticians to extract content. Electronically recorded supermarket-obtained transactions offer an objective measure of food purchases; reduced bias, and improved timeliness and scale. OBJECTIVE: This systematic review assesses the use, breadth and context, and discusses the utility of electronic purchase records for dietary research (PROSPERO CRD42018103470). METHODS: Four electronic databases were searched. Included studies used electronically recorded supermarket transactions to investigate the diet of healthy free-living adults. RESULTS: Searches identified 3,422 papers; of these 145 full texts were retrieved and 72 papers met inclusion criteria. Purchase records were used in observational studies, policy evaluations and experimental designs. Nutrition outcomes included dietary patterns, nutrients and food category sales. Transactions were linked to nutrient data from retailers, commercial data sources, and national Food Composition Databases. CONCLUSIONS: Electronic sales data has the potential to transform dietary assessment and worldwide understanding of dietary behaviour. Validation studies are warranted to understand limits to agreement and extrapolation to individual-level diets.

Key words: Supermarket, transactions, dietary assessment, dietary surveillance, methods