Iron nutritional state in breastfed and cow's milk fed mapuche infantsBlood hemoglobin, serum iron, total iron binding capacity (TIBC) and serum ferritin were measured in 140 healthy rural mapuche (southern Chile's indigenous ethnic group) infants aged 8 to 15 months: 90 had been exclusively breast fed for the first 5 or 6 months of life, then solid foods were introduced but cow's milk was never given to them. The remaining 50, which were all weaned at nearly 4 months of age and then given cow's milk and solid foods at the corresponding age, were designated as controls. Anemia was detected in 4.5% of breast fed infants and in 38% of controls. Evidence of iron deficient erythropoyesis was found in 5% and 81% of cases and controls, respectively. Human milk apparently protects this ethnic group from iron deficiency anemia and this protection seems to be better in mapuche infants than in other groups of Chilean infants, because these late have showTi 30% incidence of anemia around the first year of life in other studies. More studies on differences in iron nutritional state among mapuche and non mapuche are needed and are under way. (Key word*: iron nutrition, iron defficiency, anemia, breast feeding, cow's milk, mapuche.) La kctancia natural tiene reconocidas ventajas nutricionales, bioqui'micas, inmunologicas, psicologicas y economicas, que favorecen a la madre y al niflo. Una de ellas, reconocida por largo tiempo, es el efecto beneficioso sobre la nutricion de hierro durante el primer semestre de vida.La nutricion de hierro durante los dos primeros afios de vida se caracteriza principalmente por gran dependencia del hierro dietario para la production diaria normal de eritrocitos. En un nino de un afto de edad y 10 kg de peso, la dieta debe proveer 30% de las necesidades de hierro para el recambio de la hemoglobina (Hb), comparado con solo 5%eneladulto. Este hecho impone en el lactante altas demandas del mineral y explica la alta frecuencia de deficiencia de e"ste en dicho perfodo. El recien nacido normal esta bastante bien provisto de hierro, pero al nacer su
