α-Lactalbumin and casein-glycomacropeptide do not affect iron absorption from formula in healthy term infants

J Nutr. 2012 Jul;142(7):1226-31. doi: 10.3945/jn.111.153890. Epub 2012 May 23.

Abstract

Iron absorption from infant formula is relatively low. α-Lactalbumin and casein-glycomacropeptide have been suggested to enhance mineral absorption. We therefore assessed the effect of α-lactalbumin and casein-glycomacropeptide on iron absorption from infant formula in healthy term infants. Thirty-one infants were randomly assigned to receive 1 of 3 formulas (4 mg iron/L, 13.1 g protein/L) from 4-8 wk to 6 mo of age: commercially available whey-predominant standard infant formula (standard formula), α-lactalbumin-enriched infant formula (α-LAC), or α-lactalbumin-enriched/casein-glycomacropeptide-reduced infant formula (α-LAC/RGMP). Nine breast-fed infants served as a reference. At 5.5 mo of age, (58)Fe was administered to all infants in a meal. Blood samples were collected 14 d later for iron absorption and iron status indices. Iron deficiency was defined as depleted iron stores, iron-deficient erythropoiesis, or iron deficiency anemia. Iron absorption (mean ± SD) was 10.3 ± 7.0% from standard formula, 8.6 ± 3.8% from α-LAC, 9.2 ± 6.5% from α-LAC/RGMP, and 12.9 ± 6.5% from breast milk, with no difference between the formula groups (P = 0.79) or all groups (P = 0.44). In the formula-fed infants only, iron absorption was negatively correlated with serum ferritin (r = -0.49; P = 0.005) and was higher (P = 0.023) in iron-deficient infants (16.4 ± 12.4%) compared with those with adequate iron status (8.6 ± 4.4%). Our findings indicate that α-lactalbumin and casein-glycomacropeptide do not affect iron absorption from infant formula in infants. Low serum ferritin concentrations are correlated with increased iron absorption from infant formula.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Iron-Deficiency / blood
  • Caseins / pharmacology*
  • Diet*
  • Erythropoiesis / drug effects
  • Female
  • Ferritins / blood
  • Humans
  • Infant
  • Infant Formula / chemistry*
  • Infant Nutritional Physiological Phenomena / drug effects*
  • Intestinal Absorption
  • Iron / blood
  • Iron / deficiency
  • Iron / pharmacokinetics*
  • Iron, Dietary / pharmacokinetics*
  • Lactalbumin / pharmacology*
  • Male
  • Nutritional Status / drug effects
  • Peptide Fragments / pharmacology*
  • Reference Values

Substances

  • Caseins
  • Iron, Dietary
  • Peptide Fragments
  • caseinomacropeptide
  • Ferritins
  • Lactalbumin
  • Iron