Iron Requirements for Infants with Cow Milk Protein Allergy

Abstract

H istorically, cow milk has been used as a major source of protein and balanced nutrition for infants and children in resource-rich and resource-constrained countries. It is a rich source of energy, protein, and calcium. It is also an important source of fat; many of its fatty acids are readily metabolized to essential omega-3 fatty acids. Regular consumption of milk during childhood has been shown to enhance bone density later in life. However, reliance upon whole pasteurized cow milk as the sole or major source of nutrition for infants during the first year of life can increase the risk for iron deficiency and, in extreme cases, iron-deficient anemia (IDA) for a number of reasons. In 1972, Woodruff et al showed that 7 of 12 infants (ages 7-17 months) with IDA who ingested between 720 and 1920 mL whole milk daily had higher albumin turnover rates than a group of 5 normal infants. Parenteral iron had no effect on albumin turnover, but replacing whole milk with reconstituted evaporated milk or soy formula decreased the high albumin turnover rates to normal levels, suggesting that large amounts of cow milk protein could result in iron and protein loss in the gastrointestinal tract. Cow milk contains low levels of ascorbic acid, a factor that increases iron absorption, and certain proteins that negatively impact iron absorption. Cow milk contains about 4 times more calcium than human milk, and calcium negatively impacts iron absorption. Furthermore, cow milk has a higher protein concentration than human milk, and ingestion of large amounts can lead to metabolic and fluid imbalances, particularly in children with febrile illnesses. Thus, several entities have recommended against whole cow milk ingestion until 9-12 months and then, only when given in moderate amounts in conjunction with appropriate complementary foods.