Mineral homeostasis in young children consuming typical U.S. diets

Abstract

Mineral requirements in young children are poorly understood, and current recommendations rely heavily on data collected in older children or adults. Our objectives were to assess the relationship between mineral (Ca, Mg, Fe, Zn, and Cu) intake in young U.S. children, and mineral absorption, excretion, and retention; and to use these data to re-examine the most recent recommended intakes. Thirty children, 1–4 y old, were studied on their usual diet. After 7 d of home adaptation they were admitted for either a 2-d or 5-d metabolic study where multiple stable isotope or Ca, Mg, Fe, Zn, and Cu were administered and mineral absorption (2-d study), or absorption and excretion (5-d study) were assessed. Fractional (%) absorption of some (Ca, Mg) but not all (Fe, Zn) minerals decreased as intake increased. Absolute (total) absorption and net retention of all the minerals increased as their intake increased. Mineral homeostasis was related to changes in fractional absorption (Ca and Mg), fecal excretion (Zn), or whole body mineral status (Fe). Our results support the current U.S. recommended intakes for 1–4-y-old children for Mg and Fe, but suggest that those for Ca and Zn are too low.