Iron absorption in breast-fed infants: Effects of age, iron status, iron supplements, and complementary foods

Magnus Domellöf, Bo Lönnerdal, Steven A. Abrams, Olle Hernell

Research output: Contribution to journalArticle

107 Citations (Scopus)

Abstract

Background: Iron supplements are often recommended for older breast-fed infants, but little is known about factors affecting iron absorption from human milk or supplements. Objective: We investigated the effects of age, iron status, and iron intake on iron absorption in healthy, term, breast-fed infants. Design: Twenty-five infants were randomly assigned to receive either 1) iron supplements (1 mg·kg -1·d -1) from 4 to 9 mo of age, 2) placebo from 4 to 6 mo and iron supplements from 6 to 9 mo, or 3) placebo from 4 to 9 mo. Infants were exclusively breast-fed to 6 mo and partially breast-fed to 9 mo of age. Iron absorption was assessed by giving 58Fe with mother's milk at 6 and 9 mo. Blood samples were obtained at 4, 6, and 9 mo, and complementary food intake was recorded at 9 mo. Results: At 6 mo, mean (±SD) fractional iron absorption from human milk was relatively low (16.4 ± 11.4%), with no significant difference between iron-supplemented and unsupplemented infants. At 9 mo, iron absorption from human milk remained low in iron-supplemented infants (16.9 ± 9.3%) but was higher (P = 0.01) in unsupplemented infants (36.7 ± 18.9%). Unexpectedly, iron absorption at 9 mo was not correlated with iron status but was significantly correlated with intake of dietary iron, including supplemental iron. Conclusions: Changes in the regulation of iron absorption between 6 and 9 mo enhance the infant's ability to adapt to a low-iron diet and provide a mechanism by which some, but not all, infants avoid iron deficiency despite low iron intakes in late infancy.

Original languageEnglish (US)
Pages (from-to)198-204
Number of pages7
JournalAmerican Journal of Clinical Nutrition
Volume76
Issue number1
StatePublished - 2002

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complementary foods
iron absorption
Dietary Supplements
breasts
Breast
Iron
iron
breast milk
Human Milk
placebos
food intake
infancy
Placebos
Dietary Iron

Keywords

  • Adaptation
  • Breast milk
  • Complementary food
  • Dietary iron intake
  • Dietary regulator
  • Human milk
  • Infants
  • Iron status
  • Iron supplements
  • Nonheme-iron absorption
  • Stable isotopes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

Iron absorption in breast-fed infants : Effects of age, iron status, iron supplements, and complementary foods. / Domellöf, Magnus; Lönnerdal, Bo; Abrams, Steven A.; Hernell, Olle.

In: American Journal of Clinical Nutrition, Vol. 76, No. 1, 2002, p. 198-204.

Research output: Contribution to journalArticle

Domellöf, Magnus ; Lönnerdal, Bo ; Abrams, Steven A. ; Hernell, Olle. / Iron absorption in breast-fed infants : Effects of age, iron status, iron supplements, and complementary foods. In: American Journal of Clinical Nutrition. 2002 ; Vol. 76, No. 1. pp. 198-204.
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N2 - Background: Iron supplements are often recommended for older breast-fed infants, but little is known about factors affecting iron absorption from human milk or supplements. Objective: We investigated the effects of age, iron status, and iron intake on iron absorption in healthy, term, breast-fed infants. Design: Twenty-five infants were randomly assigned to receive either 1) iron supplements (1 mg·kg -1·d -1) from 4 to 9 mo of age, 2) placebo from 4 to 6 mo and iron supplements from 6 to 9 mo, or 3) placebo from 4 to 9 mo. Infants were exclusively breast-fed to 6 mo and partially breast-fed to 9 mo of age. Iron absorption was assessed by giving 58Fe with mother's milk at 6 and 9 mo. Blood samples were obtained at 4, 6, and 9 mo, and complementary food intake was recorded at 9 mo. Results: At 6 mo, mean (±SD) fractional iron absorption from human milk was relatively low (16.4 ± 11.4%), with no significant difference between iron-supplemented and unsupplemented infants. At 9 mo, iron absorption from human milk remained low in iron-supplemented infants (16.9 ± 9.3%) but was higher (P = 0.01) in unsupplemented infants (36.7 ± 18.9%). Unexpectedly, iron absorption at 9 mo was not correlated with iron status but was significantly correlated with intake of dietary iron, including supplemental iron. Conclusions: Changes in the regulation of iron absorption between 6 and 9 mo enhance the infant's ability to adapt to a low-iron diet and provide a mechanism by which some, but not all, infants avoid iron deficiency despite low iron intakes in late infancy.

AB - Background: Iron supplements are often recommended for older breast-fed infants, but little is known about factors affecting iron absorption from human milk or supplements. Objective: We investigated the effects of age, iron status, and iron intake on iron absorption in healthy, term, breast-fed infants. Design: Twenty-five infants were randomly assigned to receive either 1) iron supplements (1 mg·kg -1·d -1) from 4 to 9 mo of age, 2) placebo from 4 to 6 mo and iron supplements from 6 to 9 mo, or 3) placebo from 4 to 9 mo. Infants were exclusively breast-fed to 6 mo and partially breast-fed to 9 mo of age. Iron absorption was assessed by giving 58Fe with mother's milk at 6 and 9 mo. Blood samples were obtained at 4, 6, and 9 mo, and complementary food intake was recorded at 9 mo. Results: At 6 mo, mean (±SD) fractional iron absorption from human milk was relatively low (16.4 ± 11.4%), with no significant difference between iron-supplemented and unsupplemented infants. At 9 mo, iron absorption from human milk remained low in iron-supplemented infants (16.9 ± 9.3%) but was higher (P = 0.01) in unsupplemented infants (36.7 ± 18.9%). Unexpectedly, iron absorption at 9 mo was not correlated with iron status but was significantly correlated with intake of dietary iron, including supplemental iron. Conclusions: Changes in the regulation of iron absorption between 6 and 9 mo enhance the infant's ability to adapt to a low-iron diet and provide a mechanism by which some, but not all, infants avoid iron deficiency despite low iron intakes in late infancy.

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KW - Stable isotopes

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