Iron-fortified infant formulas.

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Iron deficiency is defined as a deficit that is severe enough to limit the production of hemoglobin. Seventy-five percent of the iron found in the body is used as a constituent of hemoglobin. A deficiency in iron is extremely common among infants and can lead to anemia, but it also is prevented easily through dietary intervention.Iron deficiency anemia is most common among children between 6 months and 3 years of age. Infants of 9 to 15 months of age usually are screened routinely. Iron deficiency and infection are the most common causes of anemia. In the United States, the prevalence of iron deficiency anemia has declined significantly during the past two decades.In a term infant, iron deficiency anemia is uncommon before 4 to 6 months of age because of the abundance of iron stores at birth. After these iron stores are depleted by growth, dietary iron must be provided. Preterm infants and twins have low iron stores at birth, and because their rate of growth is more rapid, their iron stores may be depleted by 2 to 3 months of age.The iron content of human milk is much less than that of iron-fortified cow milk-based formulas,but the bioavailability of human milk iron is much higher. Compared with a regular diet, which contains about 6 mg of iron per 1,000 kcal,milk contains only approximately 1.5 mg of iron per 1,000 kcal. The time period when iron deficiency is most common (ie, 6 months to 3 years of age) is when milk is a major source of calories.Recommendations for preventing iron deficiency differ for term versus preterm infants and for formula-fed versus breastfed infants. Term breastfed infants usually do not experience a depletion of iron stores before 6 months of age. The relatively high iron stores of healthy term infants and the high bioavailability of human milk iron probably protect against iron deficiency. Because supplementary foods may interfere with the bioavailability of human milk iron, exclusively breastfed infants should receive supplementation with iron-fortified foods. No differences have been observed through 4 to 6 months of age in the iron status of exclusively breastfed infants and infants fed iron-fortified cow milk-based formulas.Iron supplementation should start when term infants are 4 to 6 months of age. Common sources of iron are iron-fortified infant formulas and cereals. The latter also is a good source of iron for breastfed infants. Supplementation should begin no later than age 2 months in preterm infants. It can be administered in the form of a single liquid ferrous sulfate preparation beginning at 1 month of age. Iron deficiency is uncommon prior to this time in preterm breastfed infants because of a decrease in hemoglobin concentration and a subsequent release of excess iron, which is more than could be reused for production of red blood cells. Iron is absorbed best when administered between or before feedings. Formula-fed preterm infants should begin to receive fortified formula no later than 1 to 2 months of age.An adequate supply of iron consists of approximately 1 mg/kg per day of elemental iron for term infants. Guidelines from the Committee on Nutrition of the American Academy of Pediatrics (AAP)recommend 2 to 3 mg/kg per day of elemental iron to a maximum of 15 mg/day for breastfed low-birthweight infants. Infants who have birthweights of more than 1,500 g can be satisfied by an iron-fortified formula containing 12 mg/L of iron, which supplies approximately 2 mg/kg of iron.Iron-fortified formulas can prevent iron deficiency in formula-fed term infants. “Unfortified” cow-milk formulas supply only 1.5 mg of iron per reconstituted liter compared with 12 mg of iron as ferrous sulfate per reconstituted liter in iron-fortified formulas. It has been argued that infants consuming “unfortified”formula should change to fortified formulas before 3 months of age because they are at risk for depleting iron stores at approximately 6 months of age. The Committee on Nutrition of the AAP has recommended that the change from human milk or formula to cow milk not occur before the age of 1 year.Potential adverse effects of high iron concentrations on the bacterial flora of the gastrointestinal tract remain in question. The low iron concentrations of human milk and its high bioavailability combine to produce very low levels of iron in the gastrointestinal lumen, which are considered to have a limiting effect on the growth of potential bacterial pathogens.