The food fortification landscape in the United States: Identification and prevalence of fortified food purchases using national household scanner data.

Understanding the effects of market-driven food fortification on micronutrient adequacy and diet quality has been hampered by insufficient data on food fortification practices and limitations of self-reported dietary intake data. First, to establish a method for identifying fortified foods using scanner data and distinguish which items in the Circana Consumer Network Panel (CNP) database are fortified with vitamin A, vitamin C, calcium, or iron. Second, to calculate the proportion of products fortified with each and any of the four micronutrients and calculate the micronutrient content of fortified foods vs unfortified foods in 17 product subcategories of beverage (e.g. 100% apple juice) and grain products (e.g. ready-to-eat cereals). To classify products, we first used an ingredients-based approach. When ingredients were unavailable, we used a nutrient content approach that we validated against the ingredients approach. We calculated the proportion of products fortified and the mean and median nutrient amounts in both fortified and unfortified items. We classified 62,841 products as fortified or not, of which 37,821 were purchased by households in 2017. The validation of the nutrient approach to classifying fortification status showed strong internal validity between classification methods. For the beverages and grain products overall, 24% and 73% were fortified, respectively, with variation by product category. Vitamin C fortification was common in 100% juice and ready-to-eat cereal (30% and 44%), vitamin A fortification was common in ready-to-eat cereal (51%), while iron and calcium fortification was more common in breads and cereals (34%-53%). Nutrient concentrations differed substantially between unfortified and fortified products. Fortification with the four micronutrients was common and varied by food category, with >50% of the Daily Value per serving observed for some categories. These results and methodological framework can help elucidate the role of fortification in nutrient intake and diet quality.