The role of meat to improve the critical iron balance during weaning.

Abstract

Iron requirements during the weaning period are the highest per unit body weight during human life, and diet is often insufficient to cover iron needs. For the first time in infant nutrition the absorption of both nonheme and heme iron from a typical weaning gruel after addition of meat with and without ascorbic acid (AA) to improve bioavailability was studied. Nonheme and heme iron absorption from gruel was measured in 33 adults using 2 radioiron isotopes--an inorganic iron salt to label nonheme iron, the other biosynthetically labeled rabbit hemoglobin to label heme iron. Iron absorption was measured from the basal gruel (based on milkpowder and cereals) and from basal gruel added 20 g red powdered meat, alone and together with 20 mg AA in 4 different trials. Nonheme iron absorption from the basal meal was 0.33 mg/1000 kcal and the increase from added 20 mg AA was 39%, whereas addition of red meat increased nonheme iron absorption by 85%. This latter increase was unexpectedly high. Total iron absorption was further increased by heme iron absorption of 0.23 mg Fe/1000 kcal. When adding both meat and AA, total iron absorption amounted to 1.08 mg iron/1000 kcal, ie, exceeding 1 mg/1000 kcal, a level estimated to correspond with daily iron requirements in 95% of infants aged 12 months. Addition of powdered red meat to weaning gruels markedly increased total iron absorption. A weaning diet with added powdered meat and AA may serve as a viable option to satisfy the body's high iron requirements during this critical period.