title: Mode of oral iron administration and the amount of iron habitually consumed do not affect iron absorption, systemic iron utilisation or zinc absorption in iron-sufficient infants: a randomised trial.
abstract: Different metabolic pathways of supplemental and fortification Fe, or inhibition of Zn absorption by Fe, may explain adverse effects of supplemental Fe in Fe-sufficient infants. We determined whether the mode of oral Fe administration or the amount habitually consumed affects Fe absorption and systemic Fe utilisation in infants, and assessed the effects of these interventions on Zn absorption, Fe and Zn status, and growth. Fe-sufficient 6-month-old infants (n 72) were randomly assigned to receive 6·6 mg Fe/d from a high-Fe formula, 1·3 mg Fe/d from a low-Fe formula or 6·6 mg Fe/d from Fe drops and a formula with no added Fe for 45 d. Fractional Fe absorption, Fe utilisation and fractional Zn absorption were measured with oral (57Fe and 67Zn) and intravenous (58Fe and 70Zn) isotopes. Fe and Zn status, infection and growth were measured. At 45 d, Hb was 6·3 g/l higher in the high-Fe formula group compared with the Fe drops group, whereas serum ferritin was 34 and 35 % higher, respectively, and serum transferrin 0·1 g/l lower in the high-Fe formula and Fe drops groups compared with the low-Fe formula group (all P<0·05). No intervention effects were observed on Fe absorption, Fe utilisation, Zn absorption, other Fe status indices, plasma Zn or growth. We concluded that neither supplemental or fortification Fe nor the amount of Fe habitually consumed altered Fe absorption, Fe utilisation, Zn absorption, Zn status or growth in Fe-sufficient infants. Consumption of low-Fe formula as the only source of Fe was insufficient to maintain Fe stores.
authors.affiliation: 1Department of Clinical Sciences,Pediatrics,Umeå University,SE-901 85 Umeå,Sweden.
authors.forename: Ewa A
authors.initials: EA
authors.lastname: Szymlek-Gay
authors.affiliation: 1Department of Clinical Sciences,Pediatrics,Umeå University,SE-901 85 Umeå,Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Domellöf
authors.affiliation: 1Department of Clinical Sciences,Pediatrics,Umeå University,SE-901 85 Umeå,Sweden.
authors.forename: Olle
authors.initials: O
authors.lastname: Hernell
authors.affiliation: 2Laboratory of Human Nutrition,Institute of Food, Nutrition and Health,ETH Zurich,CH-8092 Zurich,Switzerland.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Hurrell
authors.affiliation: 1Department of Clinical Sciences,Pediatrics,Umeå University,SE-901 85 Umeå,Sweden.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Lind
authors.affiliation: 3Department of Nutrition,University of California,Davis,CA 95616,USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Lönnerdal
authors.affiliation: 2Laboratory of Human Nutrition,Institute of Food, Nutrition and Health,ETH Zurich,CH-8092 Zurich,Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Zeder
authors.affiliation: 2Laboratory of Human Nutrition,Institute of Food, Nutrition and Health,ETH Zurich,CH-8092 Zurich,Switzerland.
authors.forename: Ines M
authors.initials: IM
authors.lastname: Egli
mesh_terms: D000284:Administration, Oral; D004311:Double-Blind Method; D004347:Drug Interactions; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007501:Iron / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D015032:Zinc / Q000493:pharmacokinetics*
chemical_list: D007501:Iron; D015032:Zinc
keywords: Infant formula; Infants; Iron absorption; Iron supplements; Iron utilisation; Randomised trials; Zinc absorption