Vitamin E concentrations in term and preterm newborns and their clinical course

Oxidative stress biomarkers in the preterm infant

Oxidative stress (OS) plays a key role in the pathophysiology of preterm infants. Accurate assessment of OS remains an analytical challenge that has been partially addressed during the last few decades. A plethora of approaches have been developed to assess preterm biofluids to demonstrate a link postnatally with preterm OS, giving rise to a set of widely employed biomarkers. However, the vast number of different analytic methods and lack of standardization hampers reliable comparison of OS-related biomarkers. In this chapter, we discuss approaches for the study of OS in prematurity with respect to methodologic considerations, the metabolic source of different biomarkers and their role in clinical studies.

A double-blind, randomized clinical trial of the effect of omega-3 fatty acids on the oxidative stress of preterm neonates fed through parenteral nutrition

BACKGROUND/OBJECTIVES

The aim of this study was to research and draw conclusions about the effect of a parenteral nutrition (PN) fat emulsion, rich in omega-3 fatty acids, on the antioxidant markers of preterm infants, when compared with a standard fat emulsion. This was a double-blind, parallel-group study conducted in Athens, Greece, using an equal randomization method.

SUBJECTS/METHODS

Thirty-eight infants were selected using a double-blind method and a computer-generated randomization list. Both groups received PN, based on the same protocols. Group A received SMOFlipid fat emulsion, while group B received the standard fat emulsion (Intralipid). Serum levels of vitamin A, E and total antioxidant potential (TAP) were measured on days 0, 7 and 14 of PN support. Clinical and biochemical data were collected on days 0, 14 and on the day of discharge.

RESULTS

Serum levels of vitamin E and A were significantly increased in group A, while only vitamin A serum level was increased in group B on the fourteenth day (group A: vitamin E: P-value=0.002, vitamin A: P-value=0.000, group B: vitamin E: P-value=0.065, vitamin A: P-value=0.000). TAP was increased only in the intervention group (group A: P-value=0.000, group B: P-value=0.287). Mild anemia was developed in both groups, while no differences were detected in the infection rate, days of hospitalization, days of ventilator support and days of phototherapy.

CONCLUSIONS

Oxidative stress was significantly reduced in those neonates fed with omega-3 fatty acids, whereas no effect was observed in the neonates fed with standard lipids. Intervention had no effect on infants' growth and clinical outcome.

Vitamin E status of the newborn in relation to gestational age, birth weight and maternal vitamin E status

1. Studies were made on the vitamin E status of the newborn as judged by cord serum vitamin E and erythrocyte haemolysis in vitro in relation to gestational age, birth weight and maternal vitamin E status in subjects belonging to low (LIG)- and high (HIG)-income groups in urban Baroda. 2. In the case of full-term infants, the mean values for maternal serum vitamin E (mg/l) for LIG (n 73) and HIG (n 43) were 9.9 (SE 0.4) and 11.6 (SE 0.5). The corresponding values for cord serum vitamin E were 3.6 (SE 0.2) and 4.6 (SE 0.2) mg/l. 3. Serum vitamin E levels (mg/l) were lower in premature infants (2.3 (SE 0.2); n 20) and low-birth-weight full-term infants (2.9 (SE 0.2); n 25) than in full-term normal infants (4.2 (SE 0.1); n 91). This was associated with differences in maternal serum vitamin E levels (7.4 (SE 0.5), 8.2 (SE 0.5) and 11.1 (SE 0.3) respectively). The differences were more marked for LIG. 4. A negative correlation was found between serum vitamin E and erythrocyte haemolysis in vitro in the case of maternal blood but not in cord blood. 5. These results suggest that maternal vitamin E deficiency is one of the features associated with prematurity and intra-uterine growth retardation.

Serum concentrations of vitamin E in healthy infants fed commercial milks

Serum vitamin E concentrations were determined in 60 term and 26 premature infants during the first 2 months of life. All infants received commercial milk formula containing vitamin E. In addition, premature infants older than 10 days were given vitamin E orally as a multivitamin preparation. Thus, daily intake of vitamin E was nearly 1.2 mg/kg body weight in term infants and 2--3 mg/kg body weight in premature infants. In term infants serum levels of vitamin E rose from 2.6 mg/l (cord blood) to 7.0 mg/l (3rd--13th day) and 9.1 mg/l (16th--25th day) and remained at 10 mg/l (in the second month of life). Hemoglobin concentration and red cell number decreased continuously due to physiological anemia of infancy. In premature infants mean values of vitamin E were the same as in term infants. Vitamin E deficiency with hemolytic anemia could be demonstrated in a 2 months old infant suffering from cystic fibrosis.

Vitamin E requirements of preterm infants

Differences between feeding practices in earlier investigations prompted the present study of iron and vitamin E supplementation in breast milk fed preterm infants. A new and highly sensitive technique for quantitation of alpha-tocopherol in serum was used. Studies on 34 infants with a birth weight below 2000 g or gestational age less than or equal to 35 weeks showed that supplementation with 16.5 mg tocopheryl acetate/day from 10 days of age resulted in a significantly higher haemoglobin concentration and lower reticulocyte count at 8-10 weeks than supplementation with 1.5 mg/day (p is less than 0.05). Studies on 23 infants with a birth weight of 2000-2499 g revealed subnormal alpha-tocopherol levels in 2 of the infants given 1.5 mg tocopheryl acetate/day but there was no effect on the haemoglobin concentration at 8-10 weeks. There were no untoward effects of an early iron supplementation with 2-3 mg Fe++ (as ferrous succinate)/kg/day. It is concluded that extra supplementation with vitamin E is advisable also in breast milk fed preterm infants. A low dosage iron supplementation from 3 weeks of age is safe.