Location: Children's Nutrition Research CenterTitle: Infant iron status affects iron absorption in Peruvian breastfed infants at 2 and 5 mo of age Author
Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2013
Publication Date: 12/1/2013
Citation: Finkelstein, J.L., O'Brien, K.O., Abrams, S.A., Zavaleta, N. 2013. Infant iron status affects iron absorption in Peruvian breastfed infants at 2 and 5 mo of age. American Journal of Clinical Nutrition. 98(6):1475-1484. Interpretive Summary: The effects of prenatal iron supplementation on maternal iron status after birth and on the newborn infant are largely unknown. We measured how much iron absorption occurs from these supplements and how giving the supplements might affect growth in exclusively breastfed infants after they are born. This was done with non-radioactive isotopes of iron analyzed by mass spectrometry. We studied breastfed Peruvian infants at 2–3 mo of age and 5–6 mo of age to see how much iron they absorbed and how they grew based on how much iron their mothers had been given before their birth. We found that extra iron supplementation before birth affected early infant growth but did not significantly improve iron status or absorption in the infants. Young, exclusively breastfed infants were able to increase iron absorption as they needed to meet their needs. Additional attention needs to be focused on optimizing iron absorption at birth and alleviating iron deficiency in young infants.
Technical Abstract: Effects of prenatal iron supplementation on maternal postpartum iron status and early infant iron homeostasis remain largely unknown. We examined iron absorption and growth in exclusively breastfed infants in relation to fetal iron exposure and iron status during early infancy. Longitudinal, paired iron-absorption (58Fe) studies were conducted in 59 exclusively breastfed Peruvian infants at 2–3 mo of age (2M) and 5–6 mo of age (5M). Infants were born to women who received >/= 5100 or </= 1320 mg supplemental prenatal Fe. Iron status was assessed in mothers and infants at 2M and 5M. Infant iron absorption from breast milk averaged 7.1% and 13.9% at 2M and 5M. Maternal iron status (at 2M) predicted infant iron deficiency (ID) at 5M. Although no infants were iron deficient at 2M, 28.6% of infants had depleted iron stores (ferritin concentration < 12 ug/L) by 5M. Infant serum ferritin decreased (P < 0.0001), serum transferrin receptor (sTfR) increased (P < 0.0001), and serum iron decreased from 2M to 5M (P < 0.01). Higher infant sTfR (P < 0.01) and breast-milk copper (P < 0.01) predicted increased iron absorption at 5M. Prenatal iron supplementation had no effects on infant iron status or breast-milk nutrient concentrations at 2M or 5M. However, fetal iron exposure predicted increased infant length at 2M (P < 0.01) and 5M (P < 0.05). Fetal iron exposure affected early infant growth but did not significantly improve iron status or absorption. Young, exclusively breastfed infants upregulated iron absorption when iron stores were depleted at both 2M and 5M.