Original article
Oxidative Stress Markers and Antioxidant Status after Oral Iron Supplementation to Very Low Birth Weight Infants

https://doi.org/10.1016/j.jpeds.2007.02.016Get rights and content

Objective

To evaluate whether our current practice of giving iron 18 mg daily to 6-week-old infants with very low birth weight (VLBW) was associated with increased oxidative stress markers or decreased antioxidant status.

Study design

The study was a prospective observational study of 21 healthy VLBW infants (born at gestational age <32 weeks, birth weight <1500 g). Blood and urine were sampled twice before starting iron supplementation at 6 weeks postnatal age and after 1 week of iron supplementation at age 7 weeks. Urine 8-isoprostane was analyzed by gas chromatography–mass spectrometry and plasma total hydroperoxides were measured. Antioxidant status was assessed by ascorbic acid (vitamin C), α-tocopherol (vitamin E), ferric-reducing ability of plasma, and plasma glutathione.

Results

After 1 week of iron supplementation, no significant changes in urine 8-isoprostane or plasma total hydroperoxides were seen, and plasma antioxidants were largely unchanged.

Conclusions

Markers of oxidative stress in urine and plasma antioxidant status in healthy VLBW infants fed human milk remained unchanged after high-dose oral iron supplementation.

Section snippets

Study Subjects

The study was performed from March 2003 to December 2004 in the neonatal intensive care unit at Ulleval University Hospital in Oslo. Healthy, fully enterally fed VLBW infants (birth weight <1500 g and born at a gestational age <32 weeks) were studied, beginning at postnatal age 5 weeks. The 2 sampling times before the iron therapy (samples taken at weeks 5 and 6) were chosen to evaluate any alterations possibly induced by age and growth, before introduction of iron.

Infants were not eligible if

Results

During the study period, 105 VLBW infants were born in the hospital. By 5 weeks of age, 6 infants had died, 14 did not fulfill the inclusion criteria (6 were too ill to enter the study, 6 required ventilator support, 1 had been given iron, and 1 needed a transfusion just before entering the study), 24 had been transferred to a local hospital, 26 were discharged home, 5 infants were participants in another study, and the parents of 4 declined participation. Of the remaining 26 infants originally

Discussion

Oxidative stress markers and plasma antioxidant status did not change significantly during the second month of life in healthy VLBW infants treated for 1 week with high doses of enteral iron supplementation. Additionally, there were no major changes in the measured variables before the introduction of iron, that is, between weeks 5 and 6, indicating no significant age-induced differences in oxidative stress markers or antioxidant status in this time period.

The 8-isoprostane is a highly reliable

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