Oxidative stress markers and antioxidant status after oral iron supplementation to very low birth weight infants.

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), alpha-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.