Meconium samples from 23 preterm infants (birth weight = 1,097 ± 359 g; gestational age 29 ± 3 weeks, mean ± SD) and 27 full-term infants (3,453 ± 476 g; 39.5 ± 1 weeks) were analyzed for zinc, copper, manganese, chromium and iron by atomic absorption spectrometry. Compared to meconium from preterm infants, full-term infants had an elevated (p < 0.05) total excretion (μg) of zinc (957 ± 545 vs. 503 ± 506), copper (245 ± 256 vs. 128 ± 94) and manganese (62 ± 55 vs. 29 ± 29), but not iron (190 ± 147 vs. 332 ± 532) or chromium (0.4 ± 0.19 vs. 0.75 ± 1.0). Two preterm infants had high losses (1.5 and 2 mg) of iron in their meconium. Zinc, copper and manganese losses into meconium appear to increase with gestation, whereas iron and chromium losses occur early in gestation and may be reabsorbed by term.
The objective of this prospective, cohort study was to compare the nutritional status of full-term infants who were fed human milk (BF, n = 29), formula (FF, n = 30) or evaporated milk formulae (EM, n = 30) for at least 3 months. Infants were seen at enrollment, 3 and 6 months, at which times a blood sample, diet record and anthropometric data were collected. Infants in the EM group received solids earlier (12 +/- 5 weeks) than did FF infants (15 +/- 4 weeks), and both were earlier than BF infants (19 +/- 4 weeks). Only 26% of the EM fed group received iron supplements as ferrous sulphate drops. Seven BF, 12 FF and 20 EM had abnormal ferritin values (< 10 ng ml-1) at 6 months. Copper intake was lower in the EM infants at 3 and 6 months. However, plasma copper and erythrocyte copper zinc superoxide dismutase (ZnCuSOD) levels did not differ between groups. Selenium intake was lower in the EM group (5 +/- 1 and 10 +/- 5 micrograms d-1; 3 and 6 months) than in the FF infants (13 +/- 4 and 19 +/- 7 micrograms d-1; 3 and 6 months). Erythrocyte SeGHSPx levels in EM infants were lower at 6 months (EM, 33.2 +/- 3.4; FF. 35.2 +/- 3.9: BF, 36.1 +/- 3.8 mU mg Hb-1). Thiamin intake (0.99 +/- 0.08 and 1.24 +/- 0.32; 3 and 6 months, mg 1000 kcal-1) was higher in the FF group than in EM infants (0.38 +/- 0.39 and 0.66 +/- 0.38; 3 and 6 months). There were more (13%) abnormal thiamin assays in the EM group at 6 months than in the BF and FF infants (0%). In conclusion, infants fed evaporated milk formula receive adequate copper but may not receive enough thiamin or selenium. Unless supplemented from birth with medicinal iron, intakes of iron will be inadequate.
During a longitudinal study, hair samples and dietary intake data were collected from 50 pre-term (mean birth weight = 1054 +/- 234 g, mean gestational age = 29 +/- 2.5 weeks) and 60 full-term infants (mean birth weight = 3509 +/- 269 g, mean gestational age = 40 +/- 1 weeks) at 3, 6 and 12 months of age. Mean daily zinc, copper and manganese intakes were calculated using three-day dietary records and test-weight data for the breast-fed infants. Hair samples were analyzed for these elements by instrumental neutron activation analyses. The medium hair zinc concentration in the pre-term group at six months (81 micrograms/g) was lower (p less than 0.05) than that of the full-term group (144 micrograms/g) and was associated with lower mean dietary zinc intakes at 3 and 6 months. At 12 months, the median hair copper (12.5 micrograms/g) and manganese (0.18 micrograms/g) concentrations for the pre-term were lower (p less than 0.05) than those of the full-term infants (Cu = 16.5 micrograms/g; Mn = 0.25 micrograms/g) and were also associated with low dietary copper and manganese intakes.
Preparation of hair specimens for trace-metal analyses is routinely done by wet- or dry-ashing. Wet-ashing is more time consuming than dry-ashing and can be dangerous. We wished to determine if dry-ashing was a suitable alternative to wet-ashing with HClO4:HNO3 or HNO3 alone in preparing hair for measurement of zinc, copper, iron, and manganese by atomic absorption spectroscopy. Concentrations of Zn, Cu, and Mn were not differently affected in hair that was dry- or wet-ashed. Analytical recovery of these elements added to hair samples ranged from 102 to 108%; day-to-day CVs were less than 5%. Fe was lost during dry-ashing of hair, and wet-ashing with HNO3 produced results for Fe comparable with those obtained with HClO4:HNO3. Therefore we recommend dry-ashing of hair to be analyzed for Zn, Cu, and Mn, but wet-ashing with HNO3 for assays of Fe.
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