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 language | English (US) |
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Pages (from-to) | 198-204 |
Number of pages | 7 |
Journal | American Journal of Clinical Nutrition |
Volume | 76 |
Issue number | 1 |
State | Published - 2002 |
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