Dietary intake of calcium, chromium, copper, iron, magnesium, manganese, and zinc: Duplicate plate values corrected using derived nutrient intake

Actual chemical analyses of self-selected diets provide the most accurate data on the nutrient intake of subgroups of the population. In this study, paired food samplings (duplicate plate technique) of all foods and beverages were analyzed for energy, calcium, chromium, copper, iron, magnesium, manganese, and zinc. These values were corrected using actual energy requirements to yield more reliable nutrient intake values. Subjects were placed on a controlled diet to determine their actual energy requirements