Enteral nutrient supply for preterm infants: commentary from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition.

The number of surviving children born prematurely has increased substantially during the last 2 decades. The major goal of enteral nutrient supply to these infants is to achieve growth similar to foetal growth coupled with satisfactory functional development. The accumulation of knowledge since the previous guideline on nutrition of preterm infants from the Committee on Nutrition of the European Society of Paediatric Gastroenterology and Nutrition in 1987 has made a new guideline necessary. Thus, an ad hoc expert panel was convened by the Committee on Nutrition of the European Society of Paediatric Gastroenterology, Hepatology, and Nutrition in 2007 to make appropriate recommendations. The present guideline, of which the major recommendations are summarised here (for the full report, see http://links.lww.com/A1480), is consistent with, but not identical to, recent guidelines from the Life Sciences Research Office of the American Society for Nutritional Sciences published in 2002 and recommendations from the handbook Nutrition of the Preterm Infant. Scientific Basis and Practical Guidelines, 2nd ed, edited by Tsang et al, and published in 2005. The preferred food for premature infants is fortified human milk from the infant's own mother, or, alternatively, formula designed for premature infants. This guideline aims to provide proposed advisable ranges for nutrient intakes for stable-growing preterm infants up to a weight of approximately 1800 g, because most data are available for these infants. These recommendations are based on a considered review of available scientific reports on the subject, and on expert consensus for which the available scientific data are considered inadequate.

Preterm infants fed fortified human milk receive less protein than they need.

OBJECTIVE: The aim of this study was to compare the actual nutrient intakes observed in a previously reported study with assumed nutrient intakes based on the customary assumptions about the composition of human milk. STUDY DESIGN: Fortified human milk is assumed to provide adequate amounts of nutrients for premature infants. This assumption holds if milk has the composition of milk expressed by mothers of premature infants during weeks 2 to 3 of lactation. The assumption does not necessarily hold for milk expressed after 2 to 3 weeks lactation. It also does not hold for donor milk, which is typically provided by mothers of term infants. The size of the disparity between assumed and actual nutrient intakes is not known. Actual nutrient intakes were available for 32 preterm infants participating in the study. Assumed nutrient intakes were calculated for these infants by substituting assumed nutrient concentrations for observed nutrient concentrations. Data were compared separately for each of the 3 study weeks. RESULT: Actual protein intakes were significantly and consistently lower than assumed protein intakes during each study week. The differences in mean intakes were large, ranging from 0.5 to 0.8 g kg(-1) per day. Differences in energy intake were small and not consistently significant. CONCLUSION: Actual intakes of protein by preterm infants fed fortified human milk are substantially lower than assumed intakes. The discrepancy may in part explain why preterm infants frequently show postnatal growth failure.

Adjustable fortification of human milk fed to preterm infants: does it make a difference?

BACKGROUND: Inadequate nutrition leading to growth failure is common among premature infants. Although fortified breast milk (breast milk plus commercially prepared fortifier) is the preferred feeding, nutrient intakes achieved with fortified breast milk fall short of meeting nutrient needs. This is mainly due to inadequate protein content of fortifiers and variability in composition of expressed breast milk. OBJECTIVE: A new adjustable fortification regimen has been designed to ensure that protein needs of premature infants are met at all times. The new regimen encompasses increasing the amount of fortifier and adding extra protein to breast milk guided by periodic determinations of blood urea nitrogen (BUN). The study tested the hypothesis that infants fed according to the new regimen have higher protein intakes and improved weight gain compared to infants fed according to standard fortification regimen. METHODS: In a prospective, controlled trial, preterm infants with birth weights of 600-1750 g and gestational ages between 26 and 34 weeks were fed their own mother's milk or banked donor milk or both. Infants were randomly assigned before 21 days of age to either the new adjustable fortification regimen or the standard regimen. The study period began when feeding volume reached 150 ml/kg/day and ended when infants reached a weight of 2000 g. Standard fortification (STD) consisted in the use of the recommended amount of fortifier. Adjustable fortification (ADJ) consisted in the use, in addition to standard fortification, of extra fortifier and supplemental protein guided by twice-weekly BUN determinations. The primary outcome was weight gain, with serum biochemical indicators and nutrient intakes as secondary outcomes. RESULTS: Thirty-two infants completed the study as planned (16 ADJ, 16 STD). Infants receiving the ADJ regimen had mean protein intakes of 2.9, 3.2 and 3.4 g/kg/day, respectively, in weeks 1, 2 and 3, whereas infants receiving the STD regimen had intakes of 2.9, 2.9, 2.8 g/kg/day, respectively. Infants on the ADJ regimen showed significantly greater gain in weight (17.5+/-3.0 vs 14.4+/-3.0 g/kg/day, P<0.01) and greater gain in head circumference (1.4+/-0.3 vs 1.0+/-0.3; P<0.05) than infants on the STD regimen. Weight and head circumference gain were significantly (P<0.05) correlated with protein intake. No significant correlations were found between growth parameters and intake of fat and energy. There were no significant differences between groups in BUN and other serum chemical values. In the ADJ group, BUN concentrations increased significantly (P<0.001) over time but were not significantly higher than in the STD group. CONCLUSION: Premature infants managed with the new adjustable fortification regimen had significantly higher weight and head circumference gains than infants managed with standard fortification. Higher protein intake appears to have been primarily responsible for the improved growth with the adjustable regimen. The new fortification method could be a solution to the problem of protein undernutrition among premature infants fed human milk.

Iron absorption during recovery from malnutrition.

OBJECTIVE: In infants and children recovering from severe malnutrition, iron deficiency is common, and the ability to absorb iron during such recovery is uncertain. The objective of this study was to determine iron absorption during recovery from malnutrition. METHODS: During the later stages of recovery from malnutrition, erythrocyte incorporation of orally administered 58Fe was determined as a surrogate for iron absorption. Based on four indices, subjects were classified as iron-sufficient, iron-deficient or indeterminate. RESULTS: Of the 25 subjects, 9 were classified as iron sufficient, 5 as indeterminate and 11 as iron deficient; all but 5 had evidence of inflammation or infection. Geometric mean erythrocyte incorporation of 58Fe was 32.0% of the dose in the iron-deficient subjects, which was not significantly different (p = 0.073) than the 13.1% in the iron-sufficient subjects. Incorporation of 58Fe by the iron-sufficient subjects did not differ significantly from that by normal subjects in the same age range. Surprisingly, we found no correlation of erythrocyte incorporation of 58Fe and reticulocyte count. CONCLUSIONS: Even in the presence of infection or inflammation, iron absorption by children during a late stage of recovery from malnutrition is not impaired.

Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood.

CONTEXT: A large body of evidence documents the role of phytoestrogens in influencing hormone-dependent states. Infants fed soy formula receive high levels of phytoestrogens, in the form of soy isoflavones, during a stage of development at which permanent effects are theoretically possible. However, a paucity of data exists on the long-term effects of infant soy formulas. OBJECTIVE: To examine the association between infant exposure to soy formula and health in young adulthood, with an emphasis on reproductive health. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study conducted from March to August 1999 among adults aged 20 to 34 years who, as infants, participated during 1965-1978 in controlled feeding studies conducted at the University of Iowa, Iowa City (248 were fed soy formula and 563 were fed cow milk formula during infancy). MAIN OUTCOME MEASURES: Self-reported pubertal maturation, menstrual and reproductive history, height and usual weight, and current health, compared based on type of formula exposure during infancy. RESULTS: No statistically significant differences were observed between groups in either women or men for more than 30 outcomes. However, women who had been fed soy formula reported slightly longer duration of menstrual bleeding (adjusted mean difference, 0.37 days; 95% confidence interval [CI], 0.06-0.68), with no difference in severity of menstrual flow. They also reported greater discomfort with menstruation (unadjusted relative risk for extreme discomfort vs no or mild pain, 1.77; 95% CI, 1.04-3.00). CONCLUSIONS: Exposure to soy formula does not appear to lead to different general health or reproductive outcomes than exposure to cow milk formula. Although the few positive findings should be explored in future studies, our findings are reassuring about the safety of infant soy formula.

Gas production by feces of infants.

BACKGROUND: Intestinal gas is thought to be the cause abdominal discomfort in infants. Little is known about the type and amount of gas produced by the infant's colonic microflora and whether diet influences gas formation. METHODS: Fresh stool specimens were collected from 10 breast-fed infants, 5 infants fed a soy-based formula, and 3 infants fed a milk-based formula at approximately 1, 2, and 3 months of age. Feces were incubated anaerobically for 4 hours at 37 degrees C followed by quantitation of hydrogen (H2), methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), methanethiol (CH3SH), and dimethyl sulfide (CH3SCH3) in the head-space. RESULTS: H2 was produced in greater amounts by breast-fed infants than by infants in either formula group, presumably the consequence of incomplete absorption of breast milk oligosaccharides. CH4 was produced in greater amounts by infants fed soy formula than by infants on other diets. CO2 was produced in similar amounts by infants in all feeding groups. Production of CH3SH was conspicuously low by feces of breast-fed infants and production of H2S was high by soy-formula-fed infants. CH3SCH3 was not detected. Only modest changes with age were observed and there was no relation between gas production and stool consistency, although stools were more likely to be malodorous when concentrations of H2S and/or CH3SH were high. CONCLUSIONS: Gas release by infant feces is strongly influenced by an infant's diet. Of particular interest are differences in production of the highly toxic sulfur gases, H2S and CH3SH, because of the role that these gases may play in certain intestinal disorders of infants.

Growth of preterm infants fed nutrient-enriched or term formula after hospital discharge.

OBJECTIVE: At hospital discharge, preterm infants may have low body stores of nutrients, deficient bone mineralization, and an accumulated energy deficit. This double-blind, randomized study evaluated the growth of premature infants with birth weights <1800 g who were fed a 22 kcal/fl oz nutrient-enriched postdischarge formula (PDF) or a 20 kcal/fl oz term-infant formula (TF) from hospital discharge to 12 months' corrected age (CA). METHODS: Infants were randomized to PDF or TF a few days before hospital discharge with stratification by gender and birth weight (<1250 g or >/=1250 g). The formulas were fed to 12 months' CA. Growth was evaluated using analysis of variance controlling for site, feeding, gender, and birth weight group. Interaction effects were also assessed. Secondary analyses included a repeated measures analysis and growth modeling. RESULTS: One hundred twenty-five infants were randomized; 74 completed to 6 months' CA and 53 to 12 months' CA. PDF-fed infants weighed more than TF-fed infants at 1 and 2 months' CA, gained more weight from study day 1 to 1 and 2 months' CA, and were longer at 3 months' CA. There were significant interactions between feeding and birth weight group-among infants with birth weights <1250 g, those fed PDF weighed more at 6 months' CA, were longer at 6 months' CA, had larger head circumferences at term 1, 3, 6, and 12 months' CA, and gained more in head circumference from study day 1 to term and to 1 month CA. The repeated measures and growth modeling analyses confirmed the analysis of variance results. The PDF formula seemed to be of particular benefit for the growth of male infants. Infants fed the PDF consumed less formula and had higher protein intakes at several time points. Energy intakes, however, were not different. CONCLUSIONS: Growth was improved in preterm infants fed a nutrient-enriched postdischarge formula after hospital discharge to 12 months' CA. Beneficial effects were most evident among infants with birth weights <1250 g, particularly for head circumference measurements.

Fluoride intake and prevalence of dental fluorosis: trends in fluoride intake with special attention to infants.

BACKGROUND: Although the predominant beneficial effect of fluoride occurs locally in the mouth, the adverse effect, dental fluorosis, occurs by the systemic route. The caries attack rate in industrialized countries, including the United States and Canada, has decreased dramatically over the past 40 years. However, the prevalence of dental fluorosis in the United States has increased during the last 30 years both in communities with fluoridated water and in communities with nonfluoridated water. Dental fluorosis is closely associated with fluoride intake during the period of tooth development. METHODS: We reviewed the major changes in infant feeding practices that have occurred since 1930 and the changes in fluoride intakes by infants and young children associated with changes in feeding practices. RESULTS AND CONCLUSIONS: Based on this review, we conclude that fluoride intakes of infants and children have shown a rather steady increase since 1930, are likely to continue to increase, and will be associated with further increase in the prevalence of enamel fluorosis unless intervention measures are instituted. RECOMMENDATIONS: We believe the most important measures that should be undertaken are (1) use, when feasible, of water low in fluoride for dilution of infant formulas; (2) adult supervision of toothbrushing by children younger than 5 years of age; and (3) changes in recommendations for administration of fluoride supplements so that such supplements are not given to infants and more stringent criteria are applied for administration to children.

Retention of iron by infants.

Throughout the world, the most common nutritional deficiency disorder of infants is iron deficiency. Developing effective strategies for preventing iron deficiency requires detailed knowledge of iron retention under ordinary living conditions. For the adult population, such knowledge is at an advanced stage, but relatively little is known about infants. Many reports of iron retention by infants have been based on the assumption that, as in normal and iron-deficient adults, 80%-100% of newly absorbed iron is promptly incorporated into circulating erythrocytes, but this assumption is not supported by available data. This communication presents a review of iron retention by term and preterm infants, as determined by metabolic balance studies or (59)Fe whole-body counting studies, and it explores the relationship between iron retention and postnatal age, iron nutritional status, iron intake (or dose), and type of feeding.

Intestinal blood loss during cow milk feeding in older infants: quantitative measurements.

OBJECTIVE: To determine the response, in terms of fecal hemoglobin excretion and clinical symptoms, of normal 9 1/2-month-old infants to being fed cow milk. DESIGN: Longitudinal (before-after) trial in which each infant was fed formula for 1 month (baseline) followed by 3 months during which cow milk was fed. SETTING: Healthy infants living in Iowa City, Iowa, a town with a population of about 60,000. MAIN OUTCOME MEASURES: Hemoglobin concentration in spot stools, 96-hour quantitative fecal hemoglobin excretion, stool characteristics, feeding-related behaviors, and iron nutritional status. RESULTS: Fecal hemoglobin concentration during formula feeding (baseline) was higher than previously observed in younger infants. Nine of 31 infants responded to cow milk feeding with increased fecal hemoglobin concentration. Fecal hemoglobin concentration (mean +/- SD) of the 9 responders rose from 1,395 +/- 856 microg/g of dry stool (baseline) to 2,711 +/- 1,732 microg/g of dry stool (P=.01). The response rate (29%) was similar to that in younger infants, but the intensity of the response was much less. Quantitative hemoglobin excretion was in general agreement with estimates based on spot stool hemoglobin concentrations. Cow milk feeding was not associated with recognizable changes in stool characteristics, nor were there clinical signs related to fecal blood loss. Iron status was similar, except that after 3 months of cow milk feeding responders showed lower (P= .047) ferritin concentrations than nonresponders. CONCLUSIONS: Cow milk-induced blood loss is present in 9 1/2-month-old infants but is of such low intensity that its clinical significance seems questionable. Nevertheless, infants without cow milk-induced blood loss were in better iron nutritional status than infants who showed blood loss.

Less than 80% of absorbed iron is promptly incorporated into erythrocytes of infants.

Erythrocyte incorporation of an administered iron isotope has been used as a surrogate for iron retention on the assumption (validated in normal and iron-deficient adults) that 80-100% of the retained isotope is promptly incorporated into circulating erythrocytes. This assumption has not been validated in infants or children. The purpose of our study was to determine concurrently in normal infants absorption and erythrocyte incorporation of the stable isotope, (58)Fe. In a preliminary study (Study 1), we demonstrated that fecal excretion of ingested isotope occurs predominantly during the first 4 d after administration but continues beyond 7 d after ingestion, that is, beyond the point at which isotope in feces can be explained either by excretion of isotope that failed to enter enterocytes or by exfoliation of isotope-enriched enterocytes. In Study 2, we administered (58)Fe to nine younger (age 20-69 d) and nine older (age 165-215 d) term infants and collected feces for 11 d. Geometric mean retention of (58)Fe by the younger infants was 31.2% of intake at 4 d and 26.9% at 11 d, and by the older infants, 35.0% at 4 d and 32.5% at 11 d. Erythrocyte incorporation of (58)Fe 14 d after ingestion was 5.2% of the dose by the younger infants and 12.5% by the older infants. Utilization of retained (11 d) isotope thus was 19.8% by the younger infants and 38.3% by the older infants. We conclude that far less than 80% of retained isotope is promptly incorporated into erythrocytes (utilized) by infants.

Erythrocyte incorporation of iron by infants: iron bioavailability from a low-iron infant formula and an evaluation of the usefulness of correcting erythrocyte incorporation values, using a reference dose or plasma ferritin concentrations.

Bioavailability of iron (Fe) from a low-Fe infant formula was determined by erythrocyte incorporation of 58Fe 14 d after administration in ten healthy, non-Fe-deficient infants. Two feeding protocols were compared, with each infant acting as his/her own control. At 140 and 154 d of age, infants were fed 1000 g of 58Fe-labelled formula (1.44 mg total Fe/1000 g) as six feeds over 24 h (Protocol A) or as two feeds/day on three consecutive days (Protocol B). A water solution with 57Fe and ascorbic acid was given separately as a reference dose in both study protocols. Erythrocyte incorporation of 58Fe and 57Fe was determined by thermal ionisation mass spectrometry. Geometric mean 58Fe incorporation was 7.6% (range 3.3-13.5%) with Protocol A as compared to 10.6% (range 6.7-18.6%) with Protocol B (P = 0.05); paired t test. Inter-individual variability of 58Fe was not reduced by correcting for the incorporation of 57Fe from the reference dose, or by correcting for plasma ferritin concentration. Fractional erythrocyte incorporation of Fe from low-Fe infant formula was in the same range as our earlier published data on erythrocyte incorporation of Fe from human milk extrinsically labelled with 58Fe (Davidsson et al. 1994a). The methodological evaluations included in this study clearly indicate the importance of using standardised study protocols when evaluating Fe bioavailability in infants. Corrections of erythrocyte incorporation data based on plasma ferritin or erythrocyte incorporation of Fe from a reference dose were not found to be useful.

Cow's milk and intestinal blood loss in late infancy.

OBJECTIVES: Young infants commonly show occult intestinal blood loss when fed cow's milk, but in older infants blood loss may be less common. This study examined intestinal blood loss in response to cow's milk feeding in normal 7(1/2)-month-old and 12-month-old infants. STUDY DESIGN: Infants (n = 62) were fed formula for 1 month and then pasteurized cow's milk for 2 months. Stools were collected for quantitative determination of hemoglobin. Iron nutritional status was assessed. RESULTS: Infants fed cow's milk from 7(1/2) months of age showed a significant increase in guaiac-positive stools and in stool hemoglobin concentration. These effects were largely limited to those infants who had been breast fed early in life. Infants fed cow's milk from 12 months of age at baseline had greater stool hemoglobin concentrations than 7(1/2)-month-old infants, but cow's milk produced no significant increase. In neither age group did cow's milk affect iron nutritional status. CONCLUSION: The response to cow's milk is attenuated in infants aged 7(1/2) months compared with younger infants. By 12 months of age, the response has disappeared entirely. We conclude that the gastrointestinal tract of healthy infants gradually loses its responsiveness to cow's milk.

Infant formula with protein-energy ratio of 1.7 g/100 kcal is adequate but may not be safe.

BACKGROUND: An adequate protein-energy ratio of infant formulas has been defined as one that permits growth similar to that of infants fed relatively generous protein-energy ratios, and serum concentrations of albumin and urea nitrogen no less than those observed in breast-fed infants. A safe ratio has been defined as one with no detectable adverse effects. The hypothesis was that a protein-energy ratio of 1.7 g/100 kcal is adequate and safe. METHODS: Healthy male infants were fed Formula 1.7, a milk-based formula, as the sole source of energy from the 8th to the 112th day of life. Weight, length, and energy intake were measured; serum albumin and urea nitrogen were determined; and the results were compared with data from appropriate reference groups of infants. RESULTS: Energy intake from 8 through 55 days was significantly higher than that of infants in the formula-fed reference group. Gain in weight was significantly more than that of the formula-fed reference group or of a breast-fed reference group, whereas gain in length was similar to that of the formula-fed reference group. Body mass index was significantly higher than that of either reference group, suggesting more fat accumulation in infants fed Formula 1.7. Plasma concentrations of albumin and urea nitrogen were similar to those of the breast-fed reference group. CONCLUSION: Infants fed Formula 1.7 received adequate intakes of protein. Because of the possibility that ad libitum feeding of diets with moderately inadequate protein-energy ratios is associated with increased food intake leading to excess weight gain, it is not possible to conclude that a protein-energy ratio of 1.7 g/100 kcal is safe.

Nutrient intakes and growth of very low birth weight infants.

OBJECTIVE: Our purpose was to determine nutrient intakes and growth of very low birth weight (VLBW) infants. STUDY DESIGN: The survey consisted of infants admitted during a 9-month period to a tertiary neonatal center. Data were obtained concerning all 51 infants born weighing <1300 gm who survived beyond 21 days of age. METHODS: At weekly intervals, intakes of fluid, energy, and protein from all sources were determined and body weight was recorded. RESULTS: During the first 2 weeks of life, intake of energy (predominantly parenteral) averaged 75 +/- 12 kcal/kg per day and intake of protein averaged 1.9 +/- 0.5 gm/kg per day. From 15 to 35 days, intake of energy (transition from parenteral to enteral) averaged 99 +/- 12 kcal/kg per day and intake of protein averaged 2.5 gm/kg per day. During the period 36 to 56 days (early enteral) and 57 days to term (late enteral), energy intakes were 108 +/- 13 and 110 +/- 15 kcal/kg per day, respectively, and protein intakes were 2.7 +/- 0.5 and 2.7 +/- 0.5 gm/kg per day, respectively. These low intakes of energy and protein (relative to presumed requirements) were explained by low intake volumes and low protein concentrations of feedings. Weight reached birth weight by 14 days of age. Subsequently, weight gains averaged 13.0, 13.8, and 11.6 gm/kg per day, respectively, in successive periods. These gains were lower than would have occurred in utero. CONCLUSION: Observed growth of VLBW infants was slow relative to in utero growth, presumably because intakes of energy and, in particular, of protein fell short of intakes needed to duplicate in utero growth. Changes in feeding practices, as well as in composition of feedings, are needed if in utero growth is to be matched.

Absorption of fat and calcium by infants fed a milk-based formula containing palm olein.

OBJECTIVE: The study tested the hypothesis that inclusion of palm olein (45% of fat) in the fat blend of a milk-based infant formula decreases the absorption of fat and calcium. METHODS: Formula PO contained palm olein (45%) in addition to soy, coconut and high-oleic sunflower oils (20%, 20%, and 15%, respectively); Formula HOS contained high-oleic safflower oil (42%) in addition to coconut and soy oils (30% and 28%, respectively) and no palm olein. Fat and calcium levels in the two formulas were similar. In a balanced crossover design, fat and calcium absorption were determined in 10 normal infants ranging in age from 22 to 192 days. In three infants metabolic balance studies with complete separation of urine and feces were performed, whereas in seven infants excreta were in part collected at home, resulting in incomplete separation of urine and feces. RESULTS: Mean (+/- SD) fecal excretion of fat was higher when Formula PO was fed than when Formula HOS was fed (0.55 +/- 0.29 vs. 0.09 +/- 0.04 g/kg/day; p < 0.001). Hence % fat absorption was lower with PO than with HOS (90.0 +/- 6.4 vs. 98.5 +/- 0.6% of intake; p < 0.01). The difference in percent fat absorption was explained by significantly (p < 0.05) lower % absorption of palmitic (16:0) and stearic (18:0) acids when Formula PO was fed than when Formula HOS was fed. Fecal excretion of calcium was higher with Formula PO than with Formula HOS (53.4 +/- 12.0 vs. 37.4 +/- 14.9 mg/kg/day; p < 0.01), and hence % calcium absorption was lower with Formula PO than with Formula HOS (37.5 +/- 11.5 vs. 57.4 +/- 14.9%; p < 0.001). CONCLUSION: Absorption of fat and calcium by normal infants is lower when palm olein provides a substantial proportion of formula fat than when formula does not contain palm olein.

Erythrocyte incorporation and absorption of 58Fe in premature infants treated with erythropoietin.

We hypothesized that treatment of very low birth weight premature infants with r-HuEPO would increase erythrocyte incorporation and gastrointestinal absorption of iron. Infants with birth weights < or = 1.25 kg and gestational ages < 31 wk were randomized to receive 6 wk of 500 U of r-HuEPO/kg/wk (epo group, n = 7) or placebo (placebo group, n = 7). All infants received daily enteral supplementation with 6 mg of elemental iron per kg. An enteral test dose of a stable iron isotope, 58Fe, was administered after the 1st ("early dosing") and 4th ("late dosing") wk of treatment. Mean (+/-SD) erythrocyte incorporation of the dose of 58Fe administered determined 2 wk after early dosing was significantly greater in the epo group compared with the placebo group (4.4% +/- 1.6 versus 2.0 +/- 1.4%, p = 0.013). In contrast, after late 58Fe dosing, there was no difference between groups in incorporation (3.8 +/- 1.6% versus 5.5 +/- 2.7%). Within the epo group, percentage erythrocyte incorporation of 58Fe did not differ between early and late dosing, whereas in the placebo group it increased 3-fold (p < 0.01). Percentage absorption of 58Fe was not different between the epo and placebo groups after both early dosing (30 +/- 22% versus 34 +/- 8%) and late dosing (32 +/- 9% versus 31 +/- 6%). Absorption of nonlabeled elemental iron and 58Fe were significantly correlated with one another. The percentage of the absorbed 58Fe dose incorporated into Hb was not different between groups. We conclude that, although erythropoietin treatment stimulates erythrocyte iron incorporation in premature infants, it has no effect on iron absorption at the r-HuEPO dose studied.