Estimating nutrient intakes from food frequency questionnaires (FFQs)

1. Select an appropriate food composition database (as above).
2. Match foods listed in the DAT with entries in food composition database
3. For FFQs that do not record amounts of foods, portion sizes need to be allocated (as above).
4. Allocate frequency weights based on responses:
   weight of each food/group consumed =
   frequency (e.g. 1.0 for once a day)*portion size
5. Total nutrient intake =
   ∑ (weight * nutrient content from food composition database)

In some cases, the nutrient content may be modified by responses to other questions, e.g. the brand of margarine used, or the type of cooking fat usually used or if fat is normally cut off meat.