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), 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.

Abbreviations: 2,3-dinor, 2,3 dinor-8-isoprostaglandin F_2α, 8-isoprostane, 8-iso-prostaglandin F_2α, FRAP, Ferric-reducing ability of plasma, GGT, Gamma-glutamyl transferase, HPLC, High-performance liquid chromatography, RBC, Red blood cells, VLBW, Very low birth weight