Nutrient database development: a historical perspective from the Framingham Nutrition Studies.

Food frequency questionnaires (FFQs) are commonly used in nutritional epidemiology to assess habitual eating habits. Development of an appropriate food and nutrient database is required for translating information derived from FFQs into estimates of nutrient intake, dietary quality, or for absolute or rank-ordered nutritional risk assessment. We discuss the procedures used recently in designing a historical nutrient database to analyze an FFQ administered in 1984-1988 to Framingham Offspring-Spouse Study members. This systematic approach should inform other research in the field. The self-administered 145-item Framingham FFQ is semi-quantitative with seven nonoverlapping response categories to determine annual consumption frequency. The database development process included selection of the US Department of Agriculture's Nutrient Database for Standard Reference as the primary raw data source, expansion of the 145 FFQ line items to code individual foods to assign nutrient values, a selection process to match foods to appropriate nutrition codes for nutrient information, and a statistical model to calculate nutrient intakes. The historical database contains 449 foods and nutrient data for all 29 nutrients available in 1985. The adequacy with which an FFQ can provide reliable diet assessment data depends on the integrity of the underlying database. We outlined a systematic protocol to derive usual dietary intake from an FFQ using a robust nutrient database that is appropriate for the Framingham Offspring-Spouse Study FFQ and its assessment time-frame. The database can be updated to accommodate changes in the food supply and eating behaviors and creates a foundation for future nutrition research.