Estimation of usual intake distributions of nutrients and foods.

The issue of estimating usual intake distributions using daily intake data as collected by nationwide food consumption surveys is discussed. Of interest are not only the usual nutrient intake distributions based on food intake alone, but also the total nutrient intake distributions that must be based on information on food and supplement consumption. The problems of estimating usual food intake distributions and distinguishing between frequently consumed and infrequently consumed food items are considered. Data needs as well as statistical methodologies available to carry out each of the tasks outlined above are discussed, with particular reference to the integrated National Health and Nutrition Examination Survey that is now in the field. The replicated 24-h recalls should be augmented with a propensity questionnaire to improve on the estimation of intake distributions for infrequently consumed nutrients, supplements and food items.