Intakes of minerals from diets and foods: is there a need for concern?

Continuous monitoring of the food supply through the Total Diet Studies allows for the identification of changes and trends in the mineral content of foods resulting from agricultural or manufacturing practices. The studies also allow for the estimation of average daily intakes of minerals and a comparison of these intakes with Recommended Dietary Allowances. The Total Diet Studies use a small number of foods (core foods) to represent the U.S. food supply. The core foods are purchased four times per year, prepared for consumption, and analyzed for 11 nutritional minerals. The food composition data are then merged with food consumption data from national surveys to provide estimates of daily intakes of minerals for selected age-sex groups. Results of the 1982-1991 Total Diet Studies indicated that average intakes of potassium, phosphorus, selenium, iodine and manganese were adequate. Sodium could not be adequately assessed because the studies did not include discretionary salt. Intakes of calcium, magnesium, iron, zinc and copper were below recommended intakes for some age-sex groups. Studies based on clinical and biochemical measurements confirm that calcium, iron and zinc are of concern for segments of the U.S. population. There are conflicting opinions about the need for concern for copper and magnesium.