Our knowledge regarding the newborn infant's capacity to adapt when exposed to deficiency or excess of micronutrients is very limited. Infants may be born with low stores of micronutrients, due to maternal deficiency during pregnancy, and may further be exposed to a low intake of micronutrients, either from breast-milk or from weaning foods low in micronutrients or with low bioavailability. On the other side of the spectrum, infants may be exposed to micronutrient supplements, provided in an effort to counteract perceived deficiencies. In adults, homeostatic regulation of intestinal absorption of micronutrients, such as iron (Fe), copper (Cu) and zinc (Zn), is well developed and up- and down-regulation of absorption occurs. Whether such homeostatic regulation occurs in newborn infants is not known, or, if absent at birth, when it develops.