Relationship between dietary and biochemical measures of nutritional status in HANES I data.

Data from the first National Health and Nutrition Examination Survey were examined for individual 24-h dietary intakes of protein, vitamin A, thiamin, riboflavin, and iron, and for laboratory indices of the same nutrients in blood and urine. Mean intake values were close to or above reference standards for all nutrients except iron. Substandard laboratory values were recorded for: serum albumin and vitamin A--less than 3% of subjects; urinary thiamin/creatinine excretion--3 and 8% of white and Black subjects, respectively; Hb, hematocrit, and percentage transferrin saturation--5 to 15% of whites and 18 to 27% of Black subjects; serum iron--less than 6% of subjects. Individual dietary recall data were of limited value in predicting the laboratory indices; regression analyses indicated that sociodemographic variables may be of greater predictive value.