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Randomised clinical trial of parenteral selenium supplementation in preterm infants
Insights
Selenium supplementation of parenteral nutrition (PN) in preterm infants prevented selenium depletion. However, the dose was insufficient to reach levels found in breastfed infants, indicating a need for further research on optimal dosing.
Area of Science:
- Nutritional Science
- Pediatric Medicine
- Biochemistry
Background:
- Preterm infants are at risk of selenium deficiency due to limited nutritional intake.
- Parenteral nutrition (PN) is a common feeding method for preterm infants.
- Selenium is an essential trace element crucial for various physiological functions.
Purpose of the Study:
- To evaluate the safety and efficacy of selenium supplementation in parenteral nutrition for preterm infants.
- To assess the impact of 3 micrograms/kg/day of selenious acid on selenium status in preterm neonates.
Main Methods:
- A randomized controlled trial involving 38 preterm infants.
- Infants were allocated to receive either standard PN (PN-selenium) or PN supplemented with selenium (PN+selenium).
- Plasma and erythrocyte selenium levels, and glutathione peroxidase activity were measured over six weeks, with term infants serving as controls.
Main Results:
- Selenium supplementation prevented the decline in plasma and erythrocyte selenium levels observed in the non-supplemented group.
- While supplemented infants had higher selenium levels than non-supplemented ones, they remained lower than those in breastfed term infants.
- Urinary selenium excretion was significantly higher in the supplemented group.
Conclusions:
- Selenium supplementation at 3 micrograms/kg/day in PN is safe and prevents selenium depletion in preterm newborns.
- This dosage is insufficient to achieve selenium concentrations comparable to those in breastfed term infants.
- Further studies are needed to determine optimal selenium dosage and form for preterm infants, considering urinary excretion.
Aim:
To determine whether selenium supplementation of parenteral nutrition with 3 micrograms/kg/day of selenious acid is safe and effective in improving the selenium status of preterm infants.
Methods:
Thirty eight preterm infants with mean (SEM) birthweight of 1171 (38) g and gestational age 29 (0.3) weeks were randomly allocated to a non-supplemented (PN-selenium, n = 19) or supplemented (PN+selenium, n = 19) group. The study began at 2.8 (0.2) (range 1-5) days of age. Term breastfed (n = 23) and formula fed (n = 8) infants were used as a reference group.
Results:
Initially there was no difference between the preterm groups in plasma or erythrocyte selenium or glutathione peroxidase activity. Plasma selenium declined by a mean (SEM) of -13.3 (3.2) micrograms/l from 28 (4) to 16 (3) micrograms/l over the first three weeks in the PN-selenium group, but there was no fall in the supplemented infants and no net change in either group over six weeks. Over six weeks, there was a net decline in erythrocyte selenium of -106 (27) ng/g haemoglobin in the PN-selenium group, but no change in the PN+selenium group, such that at week 6 erythrocyte selenium was lower in the PN-selenium group (401 (17) ng/g haemoglobin) than the PN+selenium group (493 (25) ng/g haemoglobin). Urinary selenium was substantially higher in the PN+selenium group at each week. Initially term and preterm plasma selenium concentrations were similar, but they increased in term breastfed infants (+17 (2) micrograms/l), with both groups of preterm infants having lower plasma selenium concentrations at week 6 compared with term breastfed infants (PN-selenium 22 (3) micrograms/l; PN+selenium 23 (4) micrograms/l and term breastfed 49 (2) micrograms/l).
Conclusions:
Selenium supplementation of PN at 3 g/kg/day prevented depletion in newborns, but was inadequate to achieve selenium concentrations equivalent to those of breastfed term infants. Whether higher doses are more effective remains to be determined, particularly in light of the high urinary selenium secretion in supplemented infants. Selenium supplementation of both parenteral nutrition and formulas is recommended, but the optimal form and dose remain unclear.