Erythrocyte incorporation of ingested stable isotope of iron (<sup>58</sup>Fe)

Janghorbani, Morteza; Ting, Bill T. G.; Fomon, Samuel J.

doi:10.1002/ajh.2830210307

Cited by 57 publications

(49 citation statements)

References 23 publications

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“…The elemental iron powder was dissolved in 1 N sulfuric acid as previously described (2) and stored under nitrogen in sealed ampoules, each containing 1.95 mg of total iron as ferrous sulfate, including 1.44 mg of '*Fe, in 5 ml. The solution pH was 1.8 k 0.1.…”

Section: Methodsmentioning

confidence: 99%

“…Two of the previously reported infants (subjects 3 165 and 3342) were given a second dose of 58Fe in the same amount and in the same manner on the next day. The first blood sample after administration of "Fe was obtained 14 The 58Fe/57Fe isotope ratio was measured by ICP/MS as described previously (2). The ratio of the least abundant (58Fe) to the next least abundant (57Fe) isotope of iron provides for the greatest precision of measurement.…”

Section: Erythrocyte Incorporationmentioning

confidence: 99%

“…Although it is well recognized that development of strategies for prevention of iron deficiency requires sound knowledge of iron absorption, studies to provide this knowledge have been impeded by reluctance to administer radioisotopes to young subjects. We have recently demonstrated the feasibility of using the least abundant stable isotope of iron, "Fe (natural abundance 0.322 weight %), for studies of iron metabolism in infants and have reported data from study of four infants (2). We reported the MIR 58/57 in erythrocytes for each of four infants at 84 and 112 days of age (baseline values) and at 140, 168, and 196 days of age.…”

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Erythrocyte Incorporation of Ingested 58-Iron by Infants

et al. 1988

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ABSTRACT. The least abundant stable isotope of iron, "Fe (natural abundance 0.322 weight %), was administered orally to infants to explore the feasibility of using a stable rather than a radioisotope in studies of iron absorption. The dose of 58Fe was given between feedings at age 126 days. The mass isotope ratio, 58Fe/57Fe, was determined in blood by inductively coupled plasma mass spectroscopy and at ages ICPJMS, inductively coupled plasma mass spectrometry MIR, mass isotope ratio MR, measured ratioIron deficiency is a leading nutritional deficiency disorder among infants and children both in industrialized and developing countries (1). Although it is well recognized that development of strategies for prevention of iron deficiency requires sound knowledge of iron absorption, studies to provide this knowledge have been impeded by reluctance to administer radioisotopes to young subjects. We have recently demonstrated the feasibility of using the least abundant stable isotope of iron, "Fe (natural abundance 0.322 weight %), for studies of iron metabolism in infants and have reported data from study of four infants (2). We reported the MIR 58/57 in erythrocytes for each of four infants at 84 and 112 days of age (baseline values) and at 140, 168, and 196 days of age. A dose of "Fe was administered to each infant under standardized conditions at 126 days of age. We concluded that 58Fe was promising as a tracer for studies of iron availability in infants.We have now studied an additional five infants and, from the pooled data, have made estimates of the apparent errors of the method. We have also demonstrated for the first time in infants

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Section: Methodsmentioning

confidence: 99%

Section: Erythrocyte Incorporationmentioning

confidence: 99%

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Erythrocyte Incorporation of Ingested 58-Iron by Infants

et al. 1988

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“…Its isotopic composition was (weight %): 93.243% 5 8~e , 6.593% 5 7~e , 0.155% ' "e, and 0.009% 5 4~e . It was converted to ferrous sulfate as described previously (6). Preparatio~l of "Fe- The 58~e-labeled supplement was given between 0900 and 1300 h, at least 3 h after the last feeding and at least 1 h before the subsequent feeding.…”

Section: Administration Of 5 8~ementioning

confidence: 99%

Erythrocyte Incorporation of Iron by 56-Day-Old Infants Fed a 58Fe-Labeled Supplement

et al. 1995

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In an effort to obtain information about absorption of supplemental iron by breast-fed infants during the early months of life, we determined erythrocyte incorporation of a stable iron isotope, administered to 56-d-old breast-fed infants in the form of a 58~e-labeled vitamin-iron supplement. Infants of similar age fed a milk-based formula low in iron (approximately 4 mg/L) were also studied. The 58~e-labeled vitamin-iron supplement was given between feedings. Fourteen days after administration of 58Fe, mean erythrocyte incorporation of the isotope was 7.8% of the dose by breast-fed infants and 4.4% of the dose by formulafed infants. The feeding-related difference was statistically significant, probably reflecting the greater quantities of inhibitors of The term infant is born with a substantial amount of iron in storage sites, and iron stores are increased as the result of decrease in circulating erythrocytes during the early weeks of life. The quantity of storage iron is then sufficient to permit the nearly doubling of erythrocyte mass and muscle mass during the first 4 mo of life, but the transfer of iron from storage sites to active tissues largely depletes storage sites of iron unless exogenous iron is provided. We therefore consider it desirable to supplement the infant's diet with iron beginning soon after birth. This suggestion is not new. More more than 25 y ago the Committee on Nutrition of the American Academy of Pediatrics (I), stated that ". . . the early use of fortified formula results in augmentation of iron stores which helps to prevent later development of iron deficiency." This recommendation for early feeding of iron-fortified formulas has been reaffirmed more recently (2, 3). We believe that for breast-fed infants as iron absorption in the intestines of formula-fed infants. With mean iron intake from the 58Fe-labeled vitamin-iron supplement of 7.99 mg for the breast-fed infants, erythrocyte incorporation of 7.8% of the dose corresponded to 0.62 mg, a value in the range of the estimated requirement for absorbed iron. We conclude that 2-mo-old breast-fed infants are able to absorb nutritionally significant amounts of iron from an iron supplement. (Pediatr Res 38: 373-378, 1995) Abbreviations BV, blood volume IR, isotope ratioAlthough we believe that it is important to augment iron stores, little is known about the extent to which iron is absorbed during the early months of life. The present study was undertaken to obtain information on this point. We studied 56-d-old breast-fed infants given a daily supplement of iron (approximately 7.5 mg/d), and, as a surrogate for iron absorption, determined erythrocyte incorporation of iron using the stable isotope, 5 8~e , as a label. To investigate further the substantially greater erythrocyte incorporation of 5 8~e by breast-fed than by formula-fed infants given a small dose of 5 s~e between feedings (5), we included in the present study a group of formula-fed infants. METHODS Subjects well as for formula-fed infants augmentation of iron storesNormal inf...

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“…It is assumed that erythrocyte incorporation of 'absorbed' iron is similar among subjects. Incorporation is estimated to be 80% in non-anemic adult subjects (Janghorbani et al, 1986). This assumption is made to avoid having to give an i.v.…”

Section: Introductionmentioning

confidence: 99%

Fractional zinc absorption using a single isotope tracer

Yeung

Schauer

2001

Eur J Clin Nutr

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Background: Fractional absorption of zinc (Zn) has been measured using dual isotopes of Zn given simultaneously. An oral test dose and an intravenous (i.v.) reference dose are administered, followed by the measurement of the double isotopic enrichment (E) in urine 48 h after administration. We postulated that an estimate of the %E in urine for a given i.v. dose of Zn may be used to eliminate the need for venipuncture and the second Zn isotope. Objectives: To determine a constant (k) for the Zn enrichment of urine after i.v. administration of a dose of labeled Zn in Zn-replete subjects. To use 'k' to calculate fractional absorption of Zn, and to compare these values to values obtained using the standard dual isotope method. Design: Single-arm cohort. Setting: The Hospital for Sick Children, Toronto, Canada. Subjects: Twenty-three healthy adults were recruited from the Metropolitan Toronto area. Seventeen subjects completed the study. Interventions: A 2.29 mg i.v. dose of 67 Zn followed immediately by a 2.50 mg oral dose of 70 Zn. Results: Population mean percentage enrichment (%E) of 67 Zn in urine was 1.43 (95% CI 1.26, 1.60). The ratio of the i.v. dose to mean %E in urine (k) was estimated to be 1.60 mg (95% CI 1.43, 1.82). There was no difference in the mean fractional absorption of Zn calculated using the single compared to the dual isotope method: 12.58% (95% CI 2.22, 22.94) vs 12.68% (95% CI 4.52, 20.85), respectively (P ¼ 0.89). The correlation coefficient between the two methods was 0.81 (P < 0.0001). Conclusions:The dual isotope method may be replaced by using a constant (k) and a single oral dose of isotopicenriched Zn to estimate fractional absorption of Zn within a population.

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Erythrocyte incorporation of ingested stable isotope of iron (⁵⁸Fe)

Cited by 57 publications

References 23 publications

Erythrocyte Incorporation of Ingested 58-Iron by Infants

Erythrocyte Incorporation of Ingested 58-Iron by Infants

Erythrocyte Incorporation of Iron by 56-Day-Old Infants Fed a 58Fe-Labeled Supplement

Fractional zinc absorption using a single isotope tracer

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Erythrocyte incorporation of ingested stable isotope of iron (58Fe)

Cited by 57 publications

References 23 publications

Erythrocyte Incorporation of Ingested 58-Iron by Infants

Erythrocyte Incorporation of Ingested 58-Iron by Infants

Erythrocyte Incorporation of Iron by 56-Day-Old Infants Fed a 58Fe-Labeled Supplement

Fractional zinc absorption using a single isotope tracer

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Erythrocyte incorporation of ingested stable isotope of iron (⁵⁸Fe)